# Python count occurrences of character in string – Count Occurrences of a Single or Multiple Characters in String and Find their Index Positions

Count occurrences of character in list python: A Python string is a collection of characters surrounded by single, double, or triple quotes. The computer does not understand the characters; instead, it stores the manipulated character as a combination of 0’s and 1’s internally.

In this article we are going to count single characters /multiple characters in a given string.

Examples:

1)Count occurrences of single characters in a given string

Input:

given_string="btechgeeks" character ='e'

Output:

count of  e is : 3

2)Count occurrences of multiple characters in a  given string

Input:

given_string="btechgeeks" character =['e' , 'c' , 's' ]

Output:

count of  e is : 3
count of  c is : 1
count of  s is : 1

## Count occurrences of single/multiple characters in a given string and indices of them

Python count occurrences of character in string: There are several methods  some of them are:

### Method #1:Using count() function

Find all occurrences of a character in a string python: The count() method in the string class returns the number of times a substring appears in the string. In simple terms, the count() method looks for a substring in a string and returns the number of times it appears.

1)Count occurrence of single character using count() function

Count occurrences of character in string python: We can count the occurrence of single character using count() as given below.

Below is the implementation:

# given string
string = "btechgeeks"
# given character which should be counted
character = 'e'
# counting the number of occurences of given character in the string
charcount = string.count(character)
print("count of ", character, "is :", charcount)


Output:

count of  e is : 3

2)Count occurrence of multiple characters using count() function

• Traverse the list of characters whose frequency is to be calculated.
• Using count function print the frequency of respective characters.

Below is the implementation:

# given string
string = "btechgeeks"
# given characters list which should be counted
charlist = ['e', 'c', 's']
# traverse the charlist
for char in charlist:
# counting the number of occurences of given character in the string
charcount = string.count(char)
print("count of ", char, "is :", charcount)


Output:

count of  e is : 3
count of  c is : 1
count of  s is : 1

### Method #2:Using Counter() function which is in collections module

Find number of occurrences of a character in a string python: Counter is a set and dict subset. Counter() takes an iterable entity as an argument and stores the elements as keys and the frequency of the elements as a value. So, in collections, if we transfer a string. When you call Counter(), you’ll get a Counter class object with characters as keys and their frequency in a string as values.

Counter() returns a Counter type object (a subclass of dict) with all characters in the string as keys and their occurrence count as values. We’ll use the [] operator to get the occurrence count of the character’s’ from it.

1)Count occurrence of single character using Counter() function

Python count how many times a character appears in a string: Counting the frequency of character using Counter() function

Below is the implementation:

from collections import Counter
# given string
string = "btechgeeks"
# given character which should be counted
character = 'e'
# counting the frequency of all characters using counter() function
freq = Counter(string)
# counting the number of occurences of given character in the string using [] operator
charcount = freq[character]
print("count of ", character, "is :", charcount)


Output:

count of  e is : 3

2)Count occurrence of multiple characters using Counter() function

• Traverse the list of characters whose frequency is to be calculated.
• We can count their frequency using [] operator

Below is the implementation:

from collections import Counter
# given string
string = "btechgeeks"
# given characters list which should be counted
charlist = ['e', 'c', 's']
# counting the frequency of all characters using counter() function
freq = Counter(string)
# traverse the charlist
for char in charlist:
# counting the number of occurences of given character in the string using [] operator
charcount = freq[char]
print("count of ", char, "is :", charcount)


Output:

count of  e is : 3
count of  c is : 1
count of  s is : 1

## Finding single character index positions in a string

### Method #3:Using regex to count and print indices of occurrences of a string

Python count occurrences in string: Build a regex pattern that matches the character to find the index positions of that character in a string. Then iterate through all of the pattern matches in the string, adding their index positions to a list.

Below is the implementation:

import re
# given main string
string = 'Hello this is BTechGeeks'
# given character
char = 'e'
# Make a regex pattern that matches the given character
pattern = re.compile(char)
# Iterate over all the matches of regex pattern
matchiterator = pattern.finditer(string)
# taking empty list
indexlist = []
# initializing count to 0
charcount = 0
for matchobject in matchiterator:
indexlist.append(matchobject.start())
charcount = charcount + 1
print("Count of given character ", char, "is :", charcount)
print("indices of given characters :", indexlist)


Output:

Count of given character  e is : 4
indices of given characters : [1, 16, 20, 21]

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