Substring is a portion of the string that can be extracted and represented as a new string. In this tutorial, we will learn how to work with Substrings in Python.
1. Creating Python String Substring
Substring can be created using either of the following methods:
Slicingsplit()method
input = 'Engineering Field'
#substring using slice
result = input[5:]
print(result)
#substring using split
result1 = input.split()
print(result1)
Output:
2. Check for the presence of a substring in a String
The presence of sub-string in a string can be checked by either of the following methods:
- By using
inoperator - By using
find()method
input = 'Medical Colleges in India.'
#using in operator
if 'India' in input:
print('Substring is present in the input.')
#using find() method
if input.find('Medical Colleges') != -1:
print('Substring is present in the input.')
Output:
Substring is present in the input.
Substring is present in the input.
3. Get the substring from a String in Python
The following are some of the methods to get the substring from a given string:
- By using
list slicing - By using
itertools.combinations()method
Example 1: By using List Slicing
str = 'Engineering Discipline'
sub1 = str[:3]
sub2 = str[6:]
print ("Resultant substring from the start: ", sub1)
print ("Resultant substring from the end: ", sub2)
Output:
Example 2: By using itertools.combinations() method
from itertools import combinations
str1 = "Safa"
print("The original string is : " + str(str1))
result = [str1[a:b] for a, b in combinations(
range(len(str1) + 1), r = 2)]
print("All substrings of string are : " + str(result))
Output:
4. Count of occurrence of a substring in a String
The count() function is used to represent the count of the characters/sub-string in the given string.
string = 'Engineering Discipline'
print('Count of Sub-string =', string.count('i'))
string1 = 'Aroma Arena'
print('Count of Sub-string =', string1.count('Ar'))
Output:
5. Get the indexes of all substring
def find_index(str1, substring):
l2 = []
length = len(str1)
index = 0
while index < length:
x = str1.find(substring, index)
if x == -1:
return l2
l2.append(x)
index = x + 1
return l2
string = 'Aroma Arena at the desert Arone.'
print(find_index(string, 'Ar'))
The above snippet of code gives us the index/position of all of the occurrence of a particular substring in a string.
Output:
[0, 6, 26]
