Strings in Python are sequence of character which is surrounded by either single quotation marks, or double quotation marks.

	
	Strings Example:
	
		"I'm going on a run"
		
		"This is my 2nd opinion"
	

Multiline Strings:

We can assign a multiline string to a variable using three (""") quotes.

	
	a = """Lorem ipsum dolor sit amet,
	
	consectetur adipiscing elit,
	
	sed do eiusmod tempor incididunt
	
	ut labore et dolore magna aliqua."""
	
	print(a)
	

String Properties in Python:

Strings in Python are Immutable. It means that it can not be changed.

	
	name = "Sameer"
	
	name[0] = 'P' // This will throw an TypeError : 'str' object does not support item assignment.
	

how to validate the immutability of an object in python:

id() : we can get the memory address of an object using id(objectName). We can compare and conclude the immutability of string using this. As shown in below code block the memory address will be different for name variable before re-assignment and after re-assignment.

		
	id(name) // This will give the memory address of name variable. 
	
	name = name.replace('S','D') 
	
	id(name)
	

Indexing in Python:

Indexing notation uses [] notation after the string(or variable assigned the string). It allows us to grab a single character from the string.

	
	Character: h   e    l    l   o
	
		Index: 0   1   2   3   4
		
Reverse Index: 0  -4  -3  -2  -1
	

Slicing in Python:

Slicing allow us to grab a subsection of mulitple characters, a "slice" of the string.

	
	syntax:
		[start:stop:step] 
	

start: is a numercial index for the slice start

stop: is the index we will go up to (but not inlude).

step: is the size of the the "jump" we take.

String Concatination in Python:

'+' is use to concatinate the strings in python.

	
	str1 = 'Hello'
	
	str 2 = 'Sameer'
	
	print(str1 + " " +str2) 
	

String Multiplication in Python:

'*' is use to mulitply the strings in python.

	
	str1 = 'H'
	
	print(str1 * 10) 
	

Print Formattng with Strings in Python:

Often we want to "inject" a variable into the string for printing. There are multiple ways to format strings for printing variables in them.

.format() method.

	
	'String here {} then also {}'.format('something1','something2') 
	
	print('The {2} {1} {0}'.format('fox', 'brown', 'quick'))
	
	print('The {q} {b} {f}'.format(f='fox', b='brown', q='quick'))
	

Float formatting follows "{value:width.precision f}".

	
	result = 100/777  // output : 0.1287001287001287
	
	print('The result is {r:2.3f}'.format(r=result))  //output: 0.129
	

• width: before decimal point length of the variable. The value will be filled with whitespaces incase the value is less than width provided.
• precision: After decimal point length of the variable we want to print.

f-strings (formatted string literals).

	
	name = 'Sameer'
	
	print(f'Hello, his name is {name})
	

Escape Characters in Python :

To insert characters that are illegal in a string, we use an escape character. An escape character is a backslash "\" followed by the character we want to insert..

Modify Strings in Python:

Python has a set of built-in methods that allows us to use on strings. However it wont change the origional string. If we want to change the origional string then we need to re-assign it. In this case the address of the variable will be changed which imply the immutable property of string. In below table optional parameter will be placed inside [].