Forem: pavanbaddi

Javascript Array Methods

pavanbaddi — Mon, 18 May 2020 04:51:48 +0000

In this tutorial, array methods are discussed.

Length property

The array.length the property acts as a counter as it keeps count on the number of items in an array. Let us look a below example

var x = [5,8,7,2,1];
console.log(x.length);

//Console Output
5

x.length outputs the number of items in array x.

push() method

The method push() is used to insert an item into the end of the array.

Syntax

array.push(item1,item2,...);

We can insert a single item or multiple items at once.

Example

var items = ["Key", "Soap", "Table"];
items.push("Slippers", "Napkin", "Charger");
console.log(items)

//Console Output
(6) ["Key", "Soap", "Table", "Slippers", "Napkin", "Charger"]

pop() Method

The method pop() remove the last item from the array and return the remove item.

Syntax

array.pop()

Example

var items = ["Key", "Soap", "Table"];
items.push("Slippers", "Napkin", "Charger");
console.log("Array before pop() method ",items)
items.pop()
console.log("Array after pop() method ",items)

//Console Output
Array before pop() method (6) ["Key", "Soap", "Table", "Slippers", "Napkin", "Charger"]
Array after pop() method (5) ["Key", "Soap", "Table", "Slippers", "Napkin"]

shift() Method

The method shift() does the opposite of thepop() method. It removes the first item from an array.

Syntax

array.shift()

Example

var items = ["Key", "Soap", "Table"];
console.log("Array before shift() method ",items);
items.shift();
console.log("Array after shift() method ",items);

//Console Output
Array before shift() method  (3) ["Key", "Soap", "Table"]
Array after shift() method  (2) ["Soap", "Table"]

unshift Method

The method unshift does the opposite of the push() method inserts a new item at the start of the array and returns a count for a number for items in an array.

Syntax

array.unshift(item1,item2,...);

Example

var items = ["Key", "Soap", "Table"];
console.log("Array before unshift() method ",items);
items.unshift("Knife", "Medicine box", "Toilet Paper");
console.log("Array after unshift() method ",items);

//Console Output
Array before unshift() method  (3) ["Key", "Soap", "Table"]
Array after unshift() method  (6) ["Knife", "Medicine box", "Toilet Paper", "Key", "Soap", "Table"]

indexOf Method

Method indexOf used to check if the item exists in an array. It takes two arguments first is an item to search and the second argument specifies from which index it should start searching. If search item exists in the array it returns its index and if search item doesn't exist then it will return -1 which means that the item does not exist in an array.

Syntax

array.indexOf(search_item, search_from_index);

Argrument search_from_index is optional argrument.

Example 1

var items = ["Key", "Soap", "Table"];
items.indexOf("Soap");

//Console Output
1 //this is index of item "Soap"

Example 2

Let us check if student name exists in array using if-statement.

var students = ["Kishor", "Suresh", "Naresh", "Sunil", "Pradeep"];
var index = students.indexOf("Naresh");
if(index != -1){
    console.log("Student name 'Naresh' exists in array at index : "+index);
}else{
    console.log("Student name 'Naresh' does not exists in array");
}

//Console Output
Student name 'Naresh' exists in array at index : 2

slice Method

The method slice is used to cut a particular position of an array. This method takes two arguments start and end. The start the argument specifies from which index it should start slicing and end argument specifies at which index it must stop slicing. It does not override the existing array and returns a new sliced array.

Syntax

array.slice(start_index, end_index);

Example

var students = ["Kishor", "Suresh", "Naresh", "Sunil", "Pradeep"];
var start_index = 2, end_index = 4;
students.slice(start_index, end_index);

//Console Output
(2) ["Naresh", "Sunil"]

MDN Doc provides an in-detail look at javascript array methods. This post is taken from thecodelearners website

Javascript Sorting Array

pavanbaddi — Sat, 16 May 2020 14:50:32 +0000

Let us consider a list of items such as [15,12,19,26,21] and we want to sort these items in ascending or descending order this can be achieved using Array Sort Methods. These methods are created while creating an array object or on the declaration. Let us look at some of the Array Sorting Methods.

array.sort() Method

Let a look at simple sort method.

var num = [6,2,1,5,8];
num.sort();

//Console Output
(5) [1, 2, 5, 6, 8]

In array num by default sort() sorts items into ascending order. Let us look at another example by sorting student names in ascending order.

var students = ["Yashwant", "Ramesh", "Abhishek", "Abhilash", "Lokesh"];
students.sort();

//Console Output
(5) ["Abhilash", "Abhishek", "Lokesh", "Ramesh", "Yashwant"]

As you can see name initialization we have specified "Abhilash" after "Abhishek" but in output, we get "Abhilash" because of letter order. The sort method also checks by letter ordering. We can take the same above example and represent it in if-else a statement.

var students = ["Yashwant", "Ramesh", "Abhishek", "Abhilash", "Lokesh"];
if(students[0]>students[2]){ //ie Yashwant > Abhishek
    console.log("Yes name Yashwant greater than Abhishek");
}else{
    console.log("No name Yashwant not greater than Abhishek");
}

array.reverse() Method

This method reverses the array.As sort() method sorts array items to ascending order calling reverse() method on sort() like sort().reverse() does the opposite of that it orders items in descending order. Let us look at a simple example

var salary = [5025.23, 4269.65, 8965.6, 2569.12];
salary.sort().reverse();

//Console Output
(4) [8965.6, 5025.23, 4269.65, 2569.12]

Sorting Array Items using Functions

Till now you have learnt about sorting items in the order. But there could be a scenario where you would want to specify a custom function for sorting in such case we must call the function with arguments inside the sort() method. Few such examples are given below

var num = [6,2,1,5,8];
num.sort(function(a,b){
    if(a<b){ return -1; // -1 means don't change let it be the same }else if(a>b){
        return 1;
    }else {
        return 0;
    }
});
console.log(num);

//Console Output
(5) [1, 2, 5, 6, 8]

Some more example related to sorting using functions Sorting in descending order

var num = [6,2,1,5,8];
num.sort(function(a,b){
    if(a<b){ return 1; }else if(a>b){
        return -1;
    }else {
        return 0;
    }
});
console.log(num);

//Console Output
(5) [8, 6, 5, 2, 1]

Sorting Student names in ascending order

var students = ["Yashwant", "Ramesh", "Abhishek", "Abhilash", "Lokesh"];
students.sort(function(x,y){
    if(x>y){
        return 1;
    }else if(x<y){
        return -1;
    }else {
        return 0;
    }
});
console.log(students);

//Console Output
(5) ["Abhilash", "Abhishek", "Lokesh", "Ramesh", "Yashwant"]

Sorting Student names in descending order

var students = ["Yashwant", "Ramesh", "Abhishek", "Abhilash", "Lokesh"];
students.sort(function(x,y){
    if(x>y){
        return -1;
    }else if(x<y){
        return 1;
    }else {
        return 0;
    }
});
console.log(students);

//Console Output
(5) ["Yashwant", "Ramesh", "Lokesh", "Abhishek", "Abhilash"]

This post was originally posted on this site

Javascript Type Conversion

pavanbaddi — Fri, 15 May 2020 07:22:52 +0000

Using type Conversion we can change the datatype of one variable to another variable.

Converting Number to String


let salary = 25000.00;
document.write(salary.toString()); 

//Output
25000

Converting String to Number

We can use built-in methods to convert strings to numbers. The methods are Number(), parseFloat(), parseInt() and we'll also be using type of statement to check its datatype.

Using Number() objects


let x = "5000.25";
let num = Number(x);
document.write(Number(num));
document.write("<br>");
document.write(typeof num);

//Output
5000.25
number

Using parseFloat() method


let x = "5000.25";
let num = parseFloat(x);
document.write(num);
document.write("<br>");
document.write(typeof num);

//Output
5000.25
number

Using parseInt() method


let x = "5000.25";
let num = parseInt(x);
document.write(num);
document.write("<br>");
document.write(typeof num);

//Output
5000
number

As you can see in parseInt() method the decimal points are omitted this is because the num variable is of type integer and does not have decimal points.

Complete article in posted on thecodelearners javascript type conversion

Javascript DataTypes

pavanbaddi — Wed, 13 May 2020 10:53:49 +0000

In this tutorial, You'll be learning about using datatypes in Javascript.

Example


let x = 16; //now x is interger
x = 12.65; //now x value is updated to float
x = "JavaScript is Amazing."; //now x value is updated to string
document.write(x);

//output
JavaScript is Amazing.

DataType types

String

Strings are a sequence of characters wrapped in double or single quotes.
Below ways, we can assign Strings.

let task_one = "Complete Homework<br>";
//OR 
let task_two = 'Complete Homework<br>';
//OR
let task_three = `Complete Homework<br>`; //this is called string literals

document.write(task_one);
document.write(task_two);
document.write(task_three);

//output
Complete Homework
Complete Homework
Complete Homework

String Concatenation

Using `+` Operator

let name = "John";
let age = 25;
let sentence = name+" is "+age+" years old";
document.write(sentence);

//output
John is 25 years old

Using String Literals


let name = "John";
let age = 25;
let sentence = `${name} is ${age} years old`;
document.write(sentence);

//output
John is 25 years old

Numbers

Adding two numbers

let a=5,b=7;
let z=a+b;
alert(z);

Add number and string

let a=5;
let b="7";
let z=a+b;
alert(z); //output 57

null type

If we don't want to initialize the value to variable than we can use null which basically means nothing.

let designation=null
alert(designation); // outputs null

undefined type

If we declare variable but don't initialize its value than the value of the variable will be undefined.

let name;
alert(name); //outputs undefined

Boolean Date-Type

Boolean types have two values that are true or false. We can also assign 1 which means true and 0 which means false.

let has_completed_howework=true;
alert(has_completed_howework); //outputs true

We can use this for conditional checking

let has_completed_howework=true;
if(has_completed_howework==true){
    alert("Student has completed homework");
}else{
    alert("Student has not completed homework");
}

I’ve included link to the whole chapter here.

Javascript Numbers

pavanbaddi — Sat, 09 May 2020 13:44:59 +0000

This post will cover topics related to assignment, condition and type checking of Numbers.

Assigning integer and float value to a number.

var salary = 25000; //this is integer value
var average = 2.569; //this is float value

typeof Reserved Word

Using typeof is a reserved word that used to get the type of variable whether it may be integer, float, object, array and strings etc.

var name = "John";
var age = 21;
var total_marks = 456.26;

console.log(typeof name);
console.log(typeof age);
console.log(typeof total_marks);

NaN reserved word

NaN means Not a Number, these cannot be used to perform the mathematical operation.

var fruit = "orange";
fruit=fruit*2;

By using with if conditions.

var fruit = "orange";
if(isNaN(fruit)){
    console.log("This is not a number");
}else{
    console.log("This is a number");
}

//Console Output
This is not a number

Using `===` equal to operator

Using === will not only check if the value is equal but also check if is of equal type.

using `==` equal to operator.

x = "10";
y = 10;
if(x==y){
    console.log("Value of x is equal to y");
}else{
    console.log("Value of x is not equal to y");
}

//Console Output
Value of x is equal to y

using `===` equal to operator.

x = "10";
y = 10;
if(x===y){
    console.log("Value of x is equal to y");
}else{
    console.log("Value of x is not equal to y");
}

//Console Output
Value of x is not equal to y

You can find the original post here

Javascript Strings - Properties and Methods with examples

pavanbaddi — Wed, 06 May 2020 04:48:23 +0000

Strings are a sequence of characters in javascript. You can create a string using single, double or using string().

Example

var sentence_one = "Very nice to see you";
var sentence_two = 'Good to see you';
console.log(sentence_one);
console.log(sentence_two);

//Console Output
Very nice to see you
Good to see you

Creating string using `String()` Class.

var desc = new String("It was a wonderful day.");
console.log(desc.toString());

//Console Output
It was a wonderful day.

We'll not be using this example in our tutorial so stick with first example.

Get string length

Every string has the property length which returns the count of characters including empty spaces.

x = "Hello World";
y = "HelloWorld";
console.log(x.length);
console.log(y.length);

//Console Output
11
10

Escape special character from string

Special Character Example

var string = "Welcome to pink city "Jaipur"";

As you can see that double quotes beside Jaipur are used for giving importance or highlighting. If we display the above string we'll receive Uncaught SyntaxError: Unexpected identifier the error in console. This is because the browser will consider both as same. We can solve this by replacing double quotes to single quotes.

var string = "Welcome to pink city 'Jaipur'";
console.log(string);

//Console Output
Welcome to pink city 'Jaipur'

Or else we can use a backslash / to escape double-quotes.

var string = "Welcome to pink city "Jaipur"";
console.log(string);

//Console Output
Welcome to pink city "Jaipur"

The first and second backslash will be before double-quotes.

var string = 'Welcome to pink city 'Jaipur'';
console.log(string);

//Console Output
Welcome to pink city 'Jaipur'

Concatenation of string

Concatenation means joining or appending two or more strings into a single string. To concatenate strings we use + operator. It is to be noted by + is also an addition operator.

var name = "Chetan";
var age = 12;
var string = name+" will be "+age+" years old on this years birth day";
console.log(string);

//Console Output
Chetan will be 12 years old on this years birth day

You can append strings and also numbers.

Split string in parts

split() a method is used to cut the string in parts this function returns an array of strings.

Syntax

str.split(separator,limit)

var names = "suresh, ramesh, vijay, kiran";
console.log(names.split(","));

//Console Output
(4) ["suresh", " ramesh", " vijay", " kiran"]

console.log(names.split(",", 2));

//Console Output
(2) ["suresh", " ramesh"]

Replace string

This method replaces specified words or any other characters of the string and returns replaced string.

Syntax

str.replace(search_value,replace_value);

Example

var names = "suresh, ramesh, vijay, kiran";
console.log(names.replace("vijay", "pavan"));

//Console Output
suresh, ramesh, pavan, kiran

You can see that the name "vijay" got replaced with "pavan".It does not modify the original string.

I’ve included a whole chapter on Javascript Strings

Javascript Variables in a nutshell

pavanbaddi — Sun, 03 May 2020 06:10:48 +0000

Initialization of variable is very easy we simple declare var keyword followed by the variable name.

Example

var name="Rakesh";

Variable created with the name name it has Rakesh as data stored in the variable name. Similarly, we'll be looking at some more examples.

var student_name="Lohit";
var roll_no=10;
var total_marks=126.5;

We can also declare multiple variables in a single line we just need to separate them using comma and end with a semicolon.

var student_name="Lohit", roll_no=10, total_marks=126.5;

Variable declare with no initial value has to value undefined.

Javascript variable is undefined

The undefined in a reserve-word, in javascript, that means the variable is declared but the value is not defined.

Naming Conventions of Variable

Variable must not have any special characters except underscore.
If a variable name is long then underscored is used to separate the words.
Example : student_name, permanent_address etc.
Empty spaces between names are not allowed.

New Standard of Variable declarations or EcmaScript Variable declarations

EcmaScript also called as ES in short sets the standard for javascript. Time to time it will introduce new concepts to Javascript. Till now we know that through var we can define variables. But there are also types of variables such as Global, local and constants variables. EcmaScript has introduced let and const keyword through which we can also declare variables.

Declare using `let`

Variable declared using let keyword specifies block-level scope or local variables. These can be accessed inside a function block which outputs an error if called outside of their scope.

let car="volvo";
car="BMW";

We have initialised car="volvo" and updating the value of the variable car="BMW".

Declare using `const`

Variables declared using const cannot be updated like regular variables. They are constants and variable must be declared and initialised once. If not then Uncaught SyntaxError: Missing initializer in const declaration the error will be given.

const y
VM1085:1 Uncaught SyntaxError: Missing initializer in const declaration //error
const x = 10; //this is correct way

I’ve included a whole chapter on using variables in javascript.

Sorting List in Python

pavanbaddi — Fri, 01 May 2020 07:35:43 +0000

In Python, Sorting is systematically arranging the data as per the given criteria. These have a lot of applications and you will be studying this in-depth.

Examples:
*) Arranging student roll numbers in ascending order
*) Displaying the products which have high sales etc

Sorting lists

Let us start with a simple example of list sorting by numbers. We'll be using a built-in method under list sort() method to get a result. Syntax

newlist.sort(optional parameters)

Below optional parameters
Option Name -- Values -- Default Value
reverse : -- True or False -- False
key -- NA -- len() method to sort on bases on length of string,custom user defined function can also be used |

Sorting numbers in Ascending order

a=[
    9,6,8,2,1,7,3
]
a.sort()
print(a)

#PYTHON OUTPUT
[1, 2, 3, 6, 7, 8, 9]

Sorting numbers in Descending order

a=[
    9,6,8,2,1,7,3
]
a.sort(reverse=True)
print(a)

#PYTHON OUTPUT
[9, 8, 7, 6, 3, 2, 1]

Sorting years with sort() using user defined function

def myfunc(e):
    return e

a=[
    2018,2015,2017,2000,2013,2011
]
a.sort(key=myfunc)

print(a)

#PYTHON OUTPUT
[2000, 2011, 2013, 2015, 2017, 2018]

Sorting names by alphabets

names = [
'John','Nancy','Amber','Peter','Bane'
]
names.sort()
print(names)#prints names in alphabetical ascending order

names.sort(reverse=True)
print(names)#prints names in alphabetical descending order

#PYTHON OUTPUT
['Amber', 'Bane', 'John', 'Nancy', 'Peter']
['Peter', 'Nancy', 'John', 'Bane', 'Amber']

Note : sort() method only sorts on list and returns None. To sort on non-list array use sorted() method.

Sorting Tuples

Sorting using sorted() method

d = (
5,2,6,1,9
)

print(sorted(d))
print(sorted(d,reverse=True))

#PYTHON OUTPUT
[1, 2, 5, 6, 9]
[9, 6, 5, 2, 1]

Sorting Dictionaries

Sorting Keys of the dictionary Below we have created a dictionary which has names in key and value. To only order keys of dictionary use d.keys() method this will return keys of that dictionary. Calling reverse=True attribute inside sorted() method will return sorted list in reverse order.

d={
0:'Amber',
1:'John',
2:'Kiran',
3:'Rakesh',
4:'Yogesh',
}

print(sorted(d.keys())) #This will order keys of dictionary in Ascending Order

print(sorted(d.keys(),reverse=True)) # Calling reverse attribute with value True will print the keys of dictionary in Descending Order

#PYTHON OUTPUT
[0, 1, 2, 3, 4]
[4, 3, 2, 1, 0]

Sorting Values in the dictionary Here we'll be using the same method as above except insisted on calling d.keys(). We'll call d.values() method which returns values of dictionary.

d={
0:'Amber',
1:'John',
2:'Kiran',
3:'Rakesh',
4:'Yogesh',
}

print(sorted(d.values())) #This will order values of dictonary in Ascending Order

print(sorted(d.values(),reverse=True)) # Calling reverse attribute with value True will print the values of dictonary in Descending Order

Advance Dictionary Sorting

In reality, there will be many cases where dictionary is multi-dimensional and need the be order. So in this tutorial, we'll be covering most of the complex multi-dimensional dict and sort them in order. Sorting dictionary by user age.

d = {
0 : {
    'username' : 'Jane154',
    'fname' : 'Jane',
    'age' : 22,
},
1 : {
    'username' : 'Humayun12',
    'fname' : 'Humayun',
    'age' : 16,
},
2 : {
    'username' : 'Rakesh45',
    'fname' : 'Rakesh',
    'age' : 29,
},
3 : {
    'username' : 'Kimmy123',
    'fname' : 'Kimmy',
    'age' : 12,
},
}

def sortByAge(e):
return e[1]['age']

print(sorted(d.items(),key=sortByAge))

print("\n\nSorting age in reverse order with tuple inside list \n\n")

print(sorted(d.items(),key=sortByAge,reverse=True))

print("\n\nSorting age in reverse order and this will return a dictionary \n")

print(dict(sorted(d.items(),key=sortByAge,reverse=True)))

#PYTHON OUTPUT
[(3, {'username': 'Kimmy123', 'fname': 'Kimmy', 'age': 12}), (1, {'username': 'Humayun12', 'fname': 'Humayun', 'age': 16}), (0, {'username': 'Jane154', 'fname': 'Jane', 'age': 22}), (2, {'username': 'Rakesh45', 'fname': 'Rakesh', 'age':29})]

Sorting age in reverse order


[(2, {'username': 'Rakesh45', 'fname': 'Rakesh', 'age': 29}), (0, {'username':'Jane154', 'fname': 'Jane', 'age': 22}), (1, {'username': 'Humayun12', 'fname': 'Humayun', 'age': 16}), (3, {'username': 'Kimmy123', 'fname': 'Kimmy', 'age':12})]




{2: {'username': 'Rakesh45', 'fname': 'Rakesh', 'age': 29}, 0: {'username': 'Jane154', 'fname': 'Jane', 'age': 22}, 1: {'username': 'Humayun12', 'fname': 'Humayun', 'age': 16}, 3: {'username': 'Kimmy123', 'fname': 'Kimmy', 'age': 12}}

Note: Dictionaries are unordered and unsorted collection on data. so like lists they don't have sort() method. But bypassing dictionary in sorted() method will return Tuple inside list in sorted order.

click here to read the complete article

Python DateTime module with programs

pavanbaddi — Thu, 30 Apr 2020 07:48:49 +0000

Python provides a DateTime module which we'll be using to work with date and time-related cases and also go through the simple program and learn their implementation of this module.

Date and Time Functions

The module is packed with a lot of functions. But in this post, we'll be discussing some basic necessary functions.

Get Current Date and Time

import datetime

current_date = datetime.datetime.today()
print(current_date)

#PYTHON OUTPUT
datetime.datetime(2020, 2, 26, 12, 59, 32, 944167)

Here datetime is module name and followed by another DateTime is a class which contains current DateTime information.

Creating a new Date and time object

from datetime import datetime
my_datetime = datetime(2020,2,26,1,15,30)
print(my_datetime)

#PYTHON OUTPUT
datetime.datetime(2020, 2, 26, 1, 15, 30)

We have imported datetime class from the module. Class datetime needs parameter through which object is created and

the positional parameters are year,month,day,hour,minute,seconds.

Convert String to DateTime object and vice-versa

from datetime import datetime
my_datetime = datetime(2020,2,26,1,15,30)

format = "On %d %B %Y, at %I hour %M minutes and %S seconds %p i saw you in walmart with your brother"
print(my_datetime.strftime(format))

#PYTHON OUTPUT
On 26 February 2020, at 01 hour 15 minutes and 30 seconds AM i saw you in walmart with your brother

format includes those special characters % which will be interpreted to their respective form. Each of those will represent a particular part of date and time.

Let's look and another example were string is converted to DateTime object and again back to the same string which was used as input to class DateTime.

from datetime import datetime

string_datetime = "2020-02-26 8:15:45 PM"
format = "%Y-%m-%d %I:%M:%S %p";
date_obj = datetime.strptime(string_datetime, format)

print("Newly created datetime object : \n")
print(date_obj)

date_object_back_to_string = date_obj.strftime(format)
print("\nConverted datetime object back to string : {}\n".format(date_object_back_to_string));


#PYTHON OUTPUT
python datetime_prog.py 
Newly created datetime object : 

2020-02-26 20:15:45

Converted datetime object back to string : 2020-02-26 08:15:45 PM

strptime(date_string,format) the method takes two arguments they are string representation of DateTime and the format of date-time which is used in this case it is string_datetime.

strftime(format) the method takes one string argument that is in which format the DateTime must be displayed. It converts DateTime object back to a string.

Datetime format code table

Python has a standardized format code for representing symbols with respective date and time representation. Some of them are given below.

Symbol Representation

%a Represents weekday's short name as Mon, Tue.

%A Represents weekday's full name such as Sunday, Monday.

%w Represents weekday as a decimal number, where 0 is Sunday and 6 is Saturday.

%d represents a decimal number of a day like 01, 15 etc

%b Represents month and displays the short name for the month such as for January as Jan, February as Feb

%B Represents months full name

%m Represents numerical name for the month

%Y Represents full 4 characters year number

If you're interested to learn more about DateTime format codes then click here to visit the official site for Python Programming.

Python Date and Time programs

Show month name from a given date

Program with accepts a date with the day-month-year format and returns the name of a month in a given date.

from datetime import datetime

print("Enter valid date with format (day-month-year) : \n")

input_date = input()

date_object = datetime.strptime(input_date,"%d-%m-%Y")
month = date_object.strftime("%B")

print("Entered date comes in month is : {}".format(month))

#PYTHON OUTPUT
Enter valid date with format (day-month-year) : 

25-03-2020
Entered date comes in month is : March

Show number of days in the month

This program takes year and month as input from the user as numeric values convert them into a DateTime object. Another object is created by incrementing month numeric value and if the month goes above 12 than is reassigned to 1 i.e first month.

from datetime import datetime

print("Enter year in format YYYY : \n")
input_year = input()
print("Enter month in number format : \n")
input_month = input()

input_date = "{}-{}".format(input_year,input_month);
format = "%Y-%m"
start_date_obj = datetime.strptime(input_date, format)

if int(input_month) < 12:
    input_month = str(int(input_month)+1)
else: 
    input_month = "1"
    input_year = int(input_year)+1

next_input_date = "{}-{}".format(input_year, input_month)
next_date_obj = datetime.strptime(next_input_date, format)

difference_in_days = (next_date_obj-start_date_obj).days

print("\n***************Output**********************\n")
print("\nYour entered year and month is : {}".format(start_date_obj))
print("\nNext month  : {}".format(next_date_obj))
print("\nDifference in days are : {}".format(difference_in_days))

#PYTHON OUTPUT 1
$ python3.8 datetime_prog.py 
Enter year in format YYYY : 

2020
Enter month in number format : 

1

***************Output**********************


Your entered year and month is : 2020-01-01 00:00:00

Next month  : 2020-02-01 00:00:00

Difference in days are : 31

#PYTHON OUTPUT 2

$ python3.8 datetime_prog.py 
Enter year in format YYYY : 

2020
Enter month in number format : 

2

***************Output**********************


Your entered year and month is : 2020-02-01 00:00:00

Next month  : 2020-03-01 00:00:00

Difference in days are : 29

difference_in_days is calculated by subtracting two different DateTime objects.

Show next upcoming month from a given month

Takes month as a number as input from user creates DateTime object and increments the month given by the user with plus 1 which gets us the next month.

from datetime import datetime

print("Enter year in format YYYY : \n")
input_year = input()
print("Enter month in number format : \n")
input_month = input()

input_date = "{}-{}".format(input_year,input_month);
format = "%Y-%m"
start_date_obj = datetime.strptime(input_date, format)

if int(input_month) < 12:
    input_month = str(int(input_month)+1)
else: 
    input_month = "1"
    input_year = int(input_year)+1

next_input_date = "{}-{}".format(input_year, input_month)
next_date_obj = datetime.strptime(next_input_date, format)

difference_in_days = (next_date_obj-start_date_obj).days

print("\n***************Output**********************\n")
print("\nYour entered year and month is : {}".format(start_date_obj))
print("\nNext month  : {}".format(next_date_obj))
print("\nDifference in days are : {}".format(difference_in_days))

#PYTHON OUTPUT 1
$ python3.8 datetime_prog.py 
Enter year in format YYYY : 

2020
Enter month in number format : 

1

***************Output**********************


Your entered year and month is : 2020-01-01 00:00:00

Next month  : 2020-02-01 00:00:00

Difference in days are : 31

#PYTHON OUTPUT 2

$ python3.8 datetime_prog.py 
Enter year in format YYYY : 

2020
Enter month in number format : 

2

***************Output**********************


Your entered year and month is : 2020-02-01 00:00:00

Next month  : 2020-03-01 00:00:00

Difference in days are : 29

Conclusion

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If you find anything difficult with our way of explanation please leave us a comment and if you have enjoyed reading our post.

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Python Functions

pavanbaddi — Wed, 29 Apr 2020 12:54:35 +0000

Functions play most of the important parts in a programming language they are a block of subprograms to execute a specific task.

Declaration of function: use def the keyword before declaring function name

def new_func():
    print("Called new_func() method")

new_func() #Calling function

#PYTHON OUTPUT
Called new_func() method

Note: You should declare function before calling else will give error name 'new_func' is not defined

new_func()

def new_func():
    print("Called new_func() method")

#PYTHON ERROR OUTPUT 
NameError: name 'new_func' is not defined

Function Parameters

For processing complex data or to supply required values for the function to process data, we must supply

parameters. The parameters may be string, primitive data types, objects or dictionary, list, tuples etc can be considered as parameters.

Note: Parameter is also called arguments.

In the below examples, we'll be using return keyword inside at the end of the function.

return is a statement returns the processed data from the function. It may be of any type.

Some examples related to function parameters.

Functions without parameter and with return values.

def new_func():
    return 15

a = new_func()

print(a)

#PYTHON OUTPUT 
15

Function with parameters and return value

def new_func(a,b):
    return a+b

a=15
b=3
k = new_func(a,b)

print(k)

#PYTHON OUTPUT 
18

Function with parameters and no return value

def new_func(a,b):
    k = a+b
    print(k)

a=15
b=3
new_func(a,b)

#PYTHON OUTPUT 
18

Function with no parameters and return value

def new_func():
    k = 12*2
    print(k)

new_func()

#PYTHON OUTPUT 
24

Function with default parameter.

def fruits(name="Apple"):
    print(name)

fruits()
fruits("Orange")

#PYTHON OUTPUT 
Apple
Orange

Recursive Functions

Recursion is a process of calling a function inside it repeatedly until the given condition is True.

To print even numbers

def even(n, i):
    if i%2==0:
        print('{} is a even number \n '.format(i))

    if i<=n:
        i+=1
        return even(n,i)
    else:
        return 0

even(10,1)

#PYTHON OUTPUT
2 is a even number

4 is a even number

6 is a even number

8 is a even number

10 is a even number

You can find complete post here

Python Sets

pavanbaddi — Tue, 28 Apr 2020 04:11:53 +0000

Python Sets are another datatype in python which are unordered and eliminates duplication of elements. Items are put one after another enclosed by curly brackets.

Creating empty Sets

By using curly brackets {} dictionary data-type.
Also python built-in constructor for sets set() is available.

Important Points about Python Sets:

1) They are an unordered and unindexed collection of datatypes.

2) Duplicate elements are not allowed in sets.

3) Unlike a list, tuples, sets cannot be accessed through index or key.

4) items in the sets are not in sequence they usually change their sequence.

Example: Create an empty Sets

create sets using curly brackets

    a={}

create sets using python built-in set constructor

    b=set()

    print(a)
    print(b)

    #PYTHON OUTPUT
    {}
    set()

Example: Initialize sets using predefined variables.

create sets using curly brackets

    a={
    'sets',
    'change',
    'their',
    'sequence'
    }

create sets using python built-in set constructor

    b=set((
    1,2,3
    ))

    print(a)
    print(b)

    #PYTHON OUTPUT
    {'sequence', 'sets', 'their', 'change'}
    {1, 2, 3}

In the above example, we can see that in sets the sequences(occurrences) of variables change.

Example: Sets Eliminate duplicate items

    a={
        1,2,3,3,2,1
    }

    print(a)#note that duplicate elements has been ommited by sets

    #PYTHON OUTPUT
    {1, 2, 3}

Accessing Sets

Items inside sets cannot be accessed using the index. To access it we have to loop sets using a for-in loop

Example

    a={
    'alice_586',
    'Alice',
    'K',
    '123456',
    }

    for i in a:
        print(i)

    #PYTHON OUTPUT
    K
    123456
    Alice
    alice_586

To verify if a given item exists in Sets

    a={
        'alice_586',
        'Alice',
        'K',
        '123456',
    }


    print('Alice' in a)# returns True
    print('Anthony' in  a)#returns False

    #PYTHON OUTPUT
    True
    False

To count the number of items present in sets use len() method.

    a = {1,2,3,4,}

    print(len(a))

    #PYTHON OUTPUT
    4

To add new items in sets use add() method under sets. But you can add only one value at a time.

    new_set = {'BMW', 'Volvo'}

    new_set.add("Jaguar")

    print(new_set)

    #PYTHON OUTPUT
    {'BMW', 'Volvo', 'Jaguar'}

To add multiple items in sets using update() method under sets.

Syntax

    sets_name.update(another sets variable)

Example

    old_set = {'BMW', 'Volvo'}

    new_set = {'Porsche', 'Bugatti', 'Pagani'}

    old_set.update(new_set)

    print(old_set)

    #PYTHON OUTPUT
    {'Bugatti', 'Volvo', 'BMW', 'Porsche', 'Pagani'}

Note : You cannot update the existing item in sets.

To remove existing item in sets use 'remove()' or 'discard()' method

    new_set = {'Asia', 'Africa', 'Europe'}
    new_set.remove('Asia')
    print(new_set)

    #PYTHON OUTPUT
    {'Europe', 'Africa'}

Note: While using 'remove()' method we must know that if the item doesn't exists. It will give 'KeyError' Error.

Insisted of remove() use discard() method.

    new_set = {'Asia', 'Africa', 'Europe'}
    new_set.remove('Asa')
    print(new_set)

    #PYTHON ERROR OUTPUT
    KeyError: 'Asa'

Using discard() method

    new_set = {'Asia', 'Africa', 'Europe'}
    new_set.discard('Asia')
    print(new_set)

    #PYTHON OUTPUT
    {'Africa', 'Europe'}

If the item does not exists.

    new_set = {'Asia', 'Africa', 'Europe'}
    new_set.discard('Asi')
    print(new_set)

    #PYTHON OUTPUT
    {'Europe', 'Asia', 'Africa'}

To clear items inside sets use clear() method under sets.

    old_set = {'BMW', 'Volvo'}

    new_set = {'Porsche', 'Bugatti', 'Pagani'}

    old_set.update(new_set)

    old_set.clear()
    print(old_set)

    #PYTHON OUTPUT
    {}

The article is taken from the code learners python sets post

Python If-Else Condition

pavanbaddi — Sun, 26 Apr 2020 11:36:59 +0000

Conditioning is the most basic operator in any programming language. Python provides some of the built-in additional tools which we'll be learning in the section of our python tutorial.

Example: To create a simple if statement.

    a=10 
    b=5

    if a > b:
        print("Yes the value of a is greater than b value.") 

    #PYTHON OUTPUT
    Yes the value of a is greater than b value.

If Else Conditional Statement

Example

    a=10
    b=11

    if a >= b:
        print("Yes the value of a is greater than b value.") 
    else:
        print("Yes the value of b is greater than a value.") 

    #PYTHON OUTPUT
    Yes the value of b is greater than a value.

Elif Conditional Statement

    user_role = 'STAFF'

    if user_role == 'ADMIN':
        print("Welcome Administrator")
    elif user_role == 'STAFF':
        print("Welcome Staff")

    #PYTHON OUTPUT
    Welcome Staff

Nested if-elif in python

Example: To check greater of 3 nos.

    a=10
    b=11
    c=9

    if a > b:
        if a > c:
        print('A is greater')
        else:
        print('C is greater')
    elif b > c:
        print("B is greater")
    else:
        print('C is greater')

    #PYTHON OUTPUT
    B is greater

Example: Short-Hand If Condition

    a=12
    b=14

    if b>a: print(b)

    #PYTHON OUTPUT
    14

Example: Short-Hand if-else condition

    a=15
    b=16

    print(a) if a>b else print(b)

    #PYTHON OUTPUT
    16

Example: Multiple conditioning use AND OR operator.

    a=35
    b=25
    c=33    
    if a>b and a>c:
        print('A is greater than B and C')
    // PYTHON OUTPUT
    A is greater than B and C
    a=30
    b=25
    c=33    
    if a>b or a>c:
        print('Because A is greater than B') #if any one condition is True
    // PYTHON OUTPUT
    Because A is greater than B

Forem: pavanbaddi

Javascript Array Methods

Length property

push() method

Syntax

Example

pop() Method

Syntax

Example

shift() Method

Syntax

Example

unshift Method

Syntax

Example

indexOf Method

Syntax

Example 1

Example 2

slice Method

Syntax

Example

Javascript Sorting Array

array.sort() Method

array.reverse() Method

Sorting Array Items using Functions

Javascript Type Conversion

Converting Number to String

Converting String to Number

Using Number() objects

Using parseFloat() method

Using parseInt() method

Javascript DataTypes

Example

DataType types

String

String Concatenation

Using + Operator

Using String Literals

Numbers

null type

undefined type

Boolean Date-Type

Javascript Numbers

Assigning integer and float value to a number.

typeof Reserved Word

NaN reserved word

Using === equal to operator

using == equal to operator.

using === equal to operator.

Javascript Strings - Properties and Methods with examples

Example

Creating string using String() Class.

Get string length

Escape special character from string

Special Character Example

Concatenation of string

Split string in parts

Syntax

Replace string

Syntax

Example

Javascript Variables in a nutshell

Example

Naming Conventions of Variable

New Standard of Variable declarations or EcmaScript Variable declarations

Declare using let

Declare using const

Sorting List in Python

Sorting lists

Sorting Tuples

Sorting Dictionaries

Advance Dictionary Sorting

Python DateTime module with programs

Date and Time Functions

Get Current Date and Time

Creating a new Date and time object

Convert String to DateTime object and vice-versa

Datetime format code table

Python Date and Time programs

Using `+` Operator

Using `===` equal to operator

using `==` equal to operator.

using `===` equal to operator.

Creating string using `String()` Class.

Declare using `let`

Declare using `const`