How do you count values in a list python?

Question

In this tutorial, we will learn about the Python List count() method with the help of examples.

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Syntax of List count()
count() Parameters
Return value from count()
Example 1: Use of count()
Example 2: Count Tuple and List Elements Inside List
Python List count()
Parameters:
ReturnValue:
Example 1: List Count
Example 2: Find the count of elements (Duplicates) in a givenlist
Below are the three solutions:
Is there a count function for lists in Python?
How do you count occurrences in a list?
What does count () do in Python?
How do I count multiple values in a list Python?

The count() method returns the number of times the specified element appears in the list.

Example

# create a list
numbers = [2, 3, 5, 2, 11, 2, 7]

# check the count of 2
count = numbers.count(2)


print('Count of 2:', count)

# Output: Count of 2: 3

Syntax of List count()

The syntax of the count() method is:

list.count(element)

count() Parameters

The count() method takes a single argument:

element - the element to be counted

Return value from count()

The count() method returns the number of times element appears in the list.

Example 1: Use of count()

# vowels list
vowels = ['a', 'e', 'i', 'o', 'i', 'u']

# count element 'i'
count = vowels.count('i')


# print count
print('The count of i is:', count)

# count element 'p'
count = vowels.count('p')


# print count
print('The count of p is:', count)

Output

The count of i is: 2
The count of p is: 0

Example 2: Count Tuple and List Elements Inside List

# random list
random = ['a', ('a', 'b'), ('a', 'b'), [3, 4]]

# count element ('a', 'b')
count = random.count(('a', 'b'))


# print count
print("The count of ('a', 'b') is:", count)

# count element [3, 4]
count = random.count([3, 4])


# print count
print("The count of [3, 4] is:", count)

Output

The count of ('a', 'b') is: 2
The count of [3, 4] is: 1

The count() is a built-in function in Python. It will return the total count of a given element in a list. The count() function is used to count elements on a list as well as a string.

In this Python tutorial, you will learn:

Python count
Python List count()
Example 1: List Count
Example 2: Find the count of elements (Duplicates) in a givenlist

Python List count()

The count() is a built-in function in Python. It will return you the count of a given element in the list.

Syntax:

list.count(element)

Parameters:

element: The element you want to find the count.

ReturnValue:

The count() method will return an integer value, i.e., the count of the given element from the given list. It returns a 0 if the value is not found in the given list.

Example 1: List Count

Following example shows the working of count() function on a list:

list1 = ['red', 'green', 'blue', 'orange', 'green', 'gray', 'green']
color_count = list1.count('green')
print('The count of color: green is ', color_count)

Output:

The count of color: green is  3

Example 2: Find the count of elements (Duplicates) in a givenlist

list1 = [2,3,4,3,10,3,5,6,3]
elm_count = list1.count(3)
print('The count of element: 3 is ', elm_count)

Output:

The count of element: 3 is  4

Summary:

The count() is a built-in function in Python. It will return you the count of a given element in a list or a string.
In the case of a list, the element to be counted needs to be given to the count() function, and it will return the count of the element.
The count() method returns an integer value.

Below are the three solutions:

Fastest is using a for loop and storing it in a Dict.

import time
from collections import Counter


def countElement(a):
    g = {}
    for i in a:
        if i in g: 
            g[i] +=1
        else: 
            g[i] =1
    return g


z = [1,1,1,1,2,2,2,2,3,3,4,5,5,234,23,3,12,3,123,12,31,23,13,2,4,23,42,42,34,234,23,42,34,23,423,42,34,23,423,4,234,23,42,34,23,4,23,423,4,23,4]


#Solution 1 - Faster
st = time.monotonic()
for i in range(1000000):
    b = countElement(z)
et = time.monotonic()
print(b)
print('Simple for loop and storing it in dict - Duration: {}'.format(et - st))

#Solution 2 - Fast
st = time.monotonic()
for i in range(1000000):
    a = Counter(z)
et = time.monotonic()
print (a)
print('Using collections.Counter - Duration: {}'.format(et - st))

#Solution 3 - Slow
st = time.monotonic()
for i in range(1000000):
    g = dict([(i, z.count(i)) for i in set(z)])
et = time.monotonic()
print(g)
print('Using list comprehension - Duration: {}'.format(et - st))

Result

#Solution 1 - Faster

{1: 4, 2: 5, 3: 4, 4: 6, 5: 2, 234: 3, 23: 10, 12: 2, 123: 1, 31: 1, 13: 1, 42: 5, 34: 4, 423: 3}
Simple for loop and storing it in dict - Duration: 12.032000000000153

#Solution 2 - Fast

Counter({23: 10, 4: 6, 2: 5, 42: 5, 1: 4, 3: 4, 34: 4, 234: 3, 423: 3, 5: 2, 12: 2, 123: 1, 31: 1, 13: 1})
Using collections.Counter - Duration: 15.889999999999418

#Solution 3 - Slow

{1: 4, 2: 5, 3: 4, 4: 6, 5: 2, 34: 4, 423: 3, 234: 3, 42: 5, 12: 2, 13: 1, 23: 10, 123: 1, 31: 1}
Using list comprehension - Duration: 33.0

Is there a count function for lists in Python?

Python List count() method returns the count of how many times a given object occurs in a List.

How do you count occurrences in a list?

Using the count() Function The "standard" way (no external libraries) to get the count of word occurrences in a list is by using the list object's count() function. The count() method is a built-in function that takes an element as its only argument and returns the number of times that element appears in the list.

What does count () do in Python?

Count() is a Python built-in function that returns the number of times an object appears in a list. The count() method is one of Python's built-in functions. It returns the number of times a given value occurs in a string or a list, as the name implies.

How do I count multiple values in a list Python?

If you want to count multiple items in a list, you can call count() in a loop. This approach, however, requires a separate pass over the list for every count() call; which can be catastrophic for performance. Use couter() method from class collections , instead.

programming python count() trong python Python count Counter Python

How do you count values in a list python?

Example

Syntax of List count()

count() Parameters

Return value from count()

Example 1: Use of count()

Example 2: Count Tuple and List Elements Inside List

Python List count()

Syntax:

Parameters:

ReturnValue:

Example 1: List Count

Example 2: Find the count of elements (Duplicates) in a givenlist

Summary:

Below are the three solutions:

Is there a count function for lists in Python?

How do you count occurrences in a list?

What does count () do in Python?

How do I count multiple values in a list Python?

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