Python program to find occurrence to each character in given string

In this article, we will learn different methods to count the occurrence of each character in a given string. Python provides several approaches ranging from manual counting to built-in modules.

Problem statement ? We are given a string, we need to find the occurrence of each character in a given string.

Here we will be discussing 3 approaches as discussed below ?

Using Manual Dictionary Approach

This brute-force approach iterates through each character and manually counts occurrences using a dictionary ?

Example

test_str = "Tutorialspoint"
# count dictionary
count_dict = {}
for i in test_str:
    # for existing characters in the dictionary
    if i in count_dict:
        count_dict[i] += 1
    # for new characters to be added
    else:
        count_dict[i] = 1

print("Count of all characters in Tutorialspoint is :\n" + str(count_dict))

Output

Count of all characters in Tutorialspoint is :
{'T': 1, 'u': 1, 't': 2, 'o': 2, 'r': 1, 'i': 2, 'a': 1, 'l': 1, 's': 1, 'p': 1, 'n': 1}

Using collections.Counter()

The Counter class from the collections module provides a convenient way to count hashable objects ?

Example

from collections import Counter

test_str = "Tutorialspoint"
# using collections.Counter() we generate a dictionary
res = Counter(test_str)
print("Count of all characters in Tutorialspoint is :\n" + str(dict(res)))

Output

Count of all characters in Tutorialspoint is :
{'T': 1, 'u': 1, 't': 2, 'o': 2, 'r': 1, 'i': 2, 'a': 1, 'l': 1, 's': 1, 'p': 1, 'n': 1}

Using Dictionary Comprehension with set()

This approach uses dictionary comprehension with set() to get unique characters and count their occurrences ?

Example

test_str = "Tutorialspoint"
# using set() to calculate unique characters in the given string
res = {i : test_str.count(i) for i in set(test_str)}
print("Count of all characters in Tutorialspoint is :\n" + str(res))

Output

Count of all characters in Tutorialspoint is :
{'p': 1, 'a': 1, 'o': 2, 'n': 1, 'T': 1, 'l': 1, 's': 1, 'r': 1, 't': 2, 'u': 1, 'i': 2}

Comparison

Conclusion

Use collections.Counter() for the most efficient and readable solution. The manual dictionary approach helps understand the counting logic, while dictionary comprehension provides a concise one-liner.