How to use Python count

The Python count function is a built-in function that can be used with various data types to count how many times an element, which is passed as an argument, appears in the data.

When to use Python count

You can use Python count in a variety of ways. It is particularly useful for frequency analysis. For example, you can use it to count the number of times certain letters or words appear in a text. You can also use Python count to search for values in sequences such as lists or Python tuples.

What is the syntax for Python count?

Using Python count isn’t particularly difficult. The function is defined in lists, strings and tuples.

sequencetype.count(element)

The count function is called in a sequence using dot notation and is given the element to be searched for as its first parameter. This can be a single number or character, as well as entire Python strings.

How to use Python count in strings

If you want to count the instances of characters in a text, you can use the count function in Python strings. In this case, you can use additional parameters in the second and third position.

string.count(element, start, end)

The optional parameters should have an integer value and specify a certain portion of the text where you want to count the specified element.

Count letters with Python count

Let’s look at an example of how to use Python count:

# count occurrences of the letter a
Tmpstring = "the occurrences of the letter a in this string are to be counted."
tmpstring.count('a')

You can then define the string that you want to carry out the count function in. The count function is given the letter ‘a’ as the parameter and will then count how often it appears in the string. As expected, it delivers a result of 2.

If you want to limit the count to the first ten letters of the string, you can change the code for the count function as follows.

tmpstring.count('a', 0, 10)

We have set the start value as 0. Since in IT, counting always begin from 0, this is the first letter of the string. In this instance, the letter ‘a’ is only searched for in the first ten characters of the string. The reason for this is that the third parameter specifies where the search should end. In this case, the Python count function delivers the result ‘0’.

Count words with Python count

You can use the Python count function for more than counting individual letters. You can also count whole words or substrings with Python count.

# count occurrences of the word "python"
tmpstring = "Python’s count method is easy to use. Python is a good programming language."
tmpstring.count("python")

In this example the count function in the variable named tmpstring is executed and it is used to search for the word ‘Python’. This counts all the occurrences of ‘Python’. This delivers a result of ‘2’.

How to use Python count in lists

There are many basic functions in Python in lists. For example, you can use the len function to find out the Python list length. The count function also supports the use of sequence types such as Python lists. It’s executed the same as using Python count in strings.

l = [1,2,3,1,4,5,1]
l.count(1)

In the example given, the variable l is saved as a list which contains different whole numbers. Then the count is executed using the integer value ‘1’. This specifies the occurrences of the number 1 within the list. The count function returns the value ‘3’ since there are three ones in the list.