How to Index and Slice Strings in Python?

In Python, indexing and slicing are techniques used to access specific characters or parts of a string. Indexing means referring to an element of an iterable by its position whereas slicing is a feature that enables accessing parts of the sequence.

Indexing Strings in Python

String Indexing allows us to access individual characters in a string. Python treats strings like lists where each character is assigned an index, starting from 0. We can access characters in a String in Two ways :

1. Accessing Characters by Positive Index Number
2. Accessing Characters by Negative Index Number

Accessing by Positive Index Number

In this type of Indexing we pass a Positive index (which we want to access) in square brackets. The index number starts from index number 0 (which denotes the first character of a string).

# declaring the string 
s = "Geeks for Geeks !"
# accessing the character of str at 0th index 
print(s[0]) 
# accessing the character of str at 6th index 
print(s[6]) 
# accessing the character of str at 10th index 
print(s[10]) 

G
f
G

Accessing by Negative Index Number

In this type of Indexing, we pass the Negative index(which we want to access) in square brackets. Here the index number starts from index number -1 (which denotes the last character of a string). Example 2 (Negative Indexing) : 

# declaring the string 
s = "Geeks for Geeks !"
# accessing the character of str at last index 
print(s[-1]) 
# accessing the character of str at 5th index from the last 
print(s[-5]) 
# accessing the character of str at 10th index from the last 
print(s[-10]) 

!
e
o

Slicing Strings in Python

String Slicing allows us to extract a part of the string. We can specify a start index, end index, and step size. The general format for slicing is:

string[start : end : step]

• start : We provide the starting index.
• end : We provide the end index(this is not included in substring).
• step : It is an optional argument that determines the increment between each index for slicing.

# declaring the string 
s ="Geeks for Geeks !"
# slicing using indexing sequence 
print(s[: 3]) 
print(s[1 : 5 : 2]) 
print(s[-1 : -12 : -2]) 

Gee
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!seGrf