Python String Count – With Examples

In python, the string function count() is used to count the frequency of a substring within a given string. That it, the count() function returns the number of times a substring occurs inside a string. In this tutorial, we’ll look at its syntax and use-cases along with some examples.

Before we proceed, here’s a quick refresher on python strings – Strings are immutable sequences of unicode characters used to handle textual data. Strings implement all common sequence operations (example, iterations, membership tests, etc). For more, check out our guide on strings and other fundamentals of python.

As mentioned above, the string function count() in python returns the number of non-overlapping occurrences of a substring in a string. It also takes optional start and end parameters. The following is its syntax:

sample_string.count(sub, start, end)

Here, sample_string is the string in which you want to find the frequency of sub.

Parameters:

  • sub: The substring to count.
  • start (optional): The starting position in the string from where the substring is to be counted.
  • end (optional): The ending position in the string till where the substring is to be counted.

Returns:

The count() function returns the integer count of the number of non-overlapping occurrences of the substring in the range [start:end] of the string.

Example 1: Count the occurrence of substring without optional parameters

# count without optional parameters
s1 = "to code or not to code"
s2 = "Do not say codecodecodecode say code"
s3 = "Python is fun"

# count the occurrence of 'code'
c1 = s1.count("code")
c2 = s2.count("code")
c3 = s3.count("code")
# print
print("Count of 'code' in s1:", c1)
print("Count of 'code' in s2:", c2)
print("Count of 'code' in s3:", c3)

Output:

Count of 'code' in s1: 2
Count of 'code' in s2: 5
Count of 'code' in s3: 0

In the above example, the python string function count() is used to count the occurrence of the substring 'code' in strings s1, s2, and s3. It returns the count of the non-overlapping occurrences of the substring as integers: 2, 5, and 0 respectively.

Example 2: Count the occurrence of substring with optional parameters

# count with optional parameters
s = "to code or not to code"

# print the count
print(s.count("code"))
print(s.count("code",3))
print(s.count("code",4))
print(s.count("code",4,22))
print(s.count("code",4,21))
print(s.count("code",18,22))
print(s.count("code",19,22))

Output:

2
2
1
1
0
1
0

In the above example, the count() function is used along with the start and/or the end optional parameters. To better understand the use of start and end parameters imagine them as the indices to slice a string, like s[start:end] and then using the count() function to get the frequency of the substring.

For more, on python string functions, refer to the python docs.


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