Python String count() Method

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The python string count() method is used to count the number of non-overlapping occurrences of the substring that is specified as the function's parameter.

The count of the substring in a particular range of that string can also be obtained by specifying the start and end of the range in the function's parameters. The start and end are optional parameters and are interpreted as in slice notation. If the substring is empty, it returns the number of empty strings between the characters which is the length of the string plus one.

In the following section, we will be learning more details about the python string count() method.

Syntax

The syntax of the python string count() method is as follows.

str.count(sub, start= 0,end=len(string))

Parameters

The following are the parameters for the python string count() method.

• sub − This parameter specifies the substring to be searched.

• start − This parameter is an integer value which specifies the starting index from which the search starts. The first character starts from the '0' index. If the start value is not specified, then the default value is '0' that is the first index.

• end − This parameter is an integer value which specifies the ending index at which the search ends. If this value is not specified, then the default search ends at the last index.

Return Value

The python string count() method returns the number of occurrences of the substring from the given input string.

Example

The python string count() method with a substring, start and end values as its parameters returns the count of number of occurrences of the substring within the specified range.

In the following example a string "Hello! Welcome to Tutorialspoint." is created. Then the substring to be counted is specified as 'i'. After that, the count() function is invoked on the string with the start value given as 3 and end values as 30 as its arguments.

str = "Hello! Welcome to Tutorialspoint.";
substr = "i";
print("The number of occurrences of the substring in the input string are: ", str.count(substr, 3, 30))

On executing the above program, the following output is generated -

The number of occurrences of the substring in the input string are:  2

Example

If the end value is not specified in the function's parameters, the last index of the string is considered as the default end value.

The following is an example to count the number of occurrences of the substring in the given string with the help of the python string count() function. In this program a string is created and the substring is also specified. Then, the count() function is invoked on the string with the substring and start values as its arguments.

str = "Hello! Welcome to Tutorialspoint.";
substr = "to";
print("The number of occurrences of the substring in the input string are: ", str.count(substr, 21))

The following is the output obtained by executing the above program -

The number of occurrences of the substring in the input string are:  0

Example

If the start and end values are not specified in the function's parameters, the zeroth index of the string is considered as the default start value and the last index of the string is considered as the default end value.

The following is an example to count the number of occurrences of the substring in the given string with the help of the python string count() function.

str = "Hello! Welcome to Tutorialspoint.";
substr = "t";
print("The number of occurrences of the substring in the input string are: ", str.count(substr))

The following output is obtained by executing the above program -

The number of occurrences of the substring in the input string are:  3

Example

If the start and end values are not specified in the function's parameters, the zeroth index of the string is considered as the default start value and the last index of the string is considered as the default end value. If the sub string is empty, it returns the number of empty strings between characters which is the length of the string plus one.

In the following example of the count() function, a string is created and an empty sub string is specified. Then, the count() function is invoked on the string without providing the start and the end values.

str = "Hello! Welcome to Tutorialspoint.";
substr = "";
print("The number of occurrences of the substring in the input string are: ", str.count(substr))

The above program, on executing, displays the following output -

The number of occurrences of the substring in the input string are:  34

Example

The substring is a mandatory parameter of the python string count() method. If this parameter is not specified, a type error is occured.

The following is an example to count the number of occurrences of the substring in the input string with the help of the python string count() function. In the following example a string is created. Then, the count() function is invoked on the string with the start and end values as its arguments but the substring to be counted is not specified.

str = "Hello! Welcome to Tutorialspoint.";
print("The number of occurrences of the substring in the input string are: ", str.count(2, 21))

The output of the above program is displayed as follows -

Traceback (most recent call last):
  File "main.py", line 2, in 
    print("The number of occurrences of the substring in the input string are: ", str.count(2, 21))
TypeError: must be str, not int