We can use Python in operator to check if a string is present in the list or not. There is also a not in operator to check if a string is not present in the list.
l1 = ['A', 'B', 'C', 'D', 'A', 'A', 'C']# string in the listif 'A' in l1: print('A is present in the list')# string not in the listif 'X' not in l1: print('X is not present in the list')Output:
A is present in the listX is not present in the listRecommended Reading: Python f-strings Let’s look at another example where we will ask the user to enter the string to check in the list.
l1 = ['A', 'B', 'C', 'D', 'A', 'A', 'C']s = input('Please enter a character A-Z:\n')if s in l1: print(f'{s} is present in the list')else: print(f'{s} is not present in the list')Output:
Please enter a character A-Z:AA is present in the listPython Find String in List using count()
We can also use count() function to get the number of occurrences of a string in the list. If its output is 0, then it means that string is not present in the list.
l1 = ['A', 'B', 'C', 'D', 'A', 'A', 'C']s = 'A'count = l1.count(s)if count > 0: print(f'{s} is present in the list for {count} times.')Finding all indexes of a string in the list
There is no built-in function to get the list of all the indexes of a string in the list. Here is a simple program to get the list of all the indexes where the string is present in the list.
l1 = ['A', 'B', 'C', 'D', 'A', 'A', 'C']s = 'A'matched_indexes = []i = 0length = len(l1)while i < length: if s == l1[i]: matched_indexes.append(i) i += 1print(f'{s} is present in {l1} at indexes {matched_indexes}')Output: A is present in ['A', 'B', 'C', 'D', 'A', 'A', 'C'] at indexes [0, 4, 5]
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