Built-in Functions in Python

Built-in Functions in Python
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Rahul Dubey

Published on Sep 28, 2021

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The Python interpreter has a number of functions and types built into it that are always available. They are listed here in alphabetical order.

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Python abs()

The abs() function returns the absolute value of the given number. If the number is a complex number, abs() returns its magnitude.

number = -20

absolute_number = abs(number)
print(absolute_number)

# Output: 20
20

Python all()

The all() function returns True if all elements in the given iterable are true. If not, it returns False.

boolean_list = ['True', 'True', 'True']

# check if all elements are true
result = all(boolean_list)
print(result)

# Output: True
True

Python any()

The any() function returns True if any element of an iterable is True. If not, it returns False.

boolean_list = ['True', 'False', 'True']

# check if any element is true
result = any(boolean_list)
print(result)

# Output: True
True

Python ascii()

The ascii() method returns a string containing a printable representation of an object. It escapes the non-ASCII characters in the string using \x, \u or \U escapes.

otherText = 'Pythön is interesting'
print(ascii(otherText))
'Pyth\xf6n is interesting'

Python bin()

The bin() method converts and returns the binary equivalent string of a given integer. If the parameter isn't an integer, it has to implement index() method to return an integer.

number = 5
print('The binary equivalent of 5 is:', bin(number))
The binary equivalent of 5 is: 0b101

Python enumerate()

The enumerate() method adds a counter to an iterable and returns it (the enumerate object).

languages = ['Python', 'Java', 'JavaScript']

enumerate_prime = enumerate(languages)

# convert enumerate object to list
print(list(enumerate_prime))

# Output: [(0, 'Python'), (1, 'Java'), (2, 'JavaScript')]
[(0, 'Python'), (1, 'Java'), (2, 'JavaScript')]

Python filter()

The filter() function extracts elements from an iterable (list, tuple etc.) for which a function returns True.

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

# returns True if number is even
def check_even(number):
    if number % 2 == 0:
          return True  

    return False

# Extract elements from the numbers list for which check_even() returns True
even_numbers_iterator = filter(check_even, numbers)

# converting to list
even_numbers = list(even_numbers_iterator)

print(even_numbers)

# Output: [2, 4, 6, 8, 10]
[2, 4, 6, 8, 10]

Python map()

The map() function applies a given function to each item of an iterable (list, tuple etc.) and returns an iterator.

numbers = [2, 4, 6, 8, 10]

# returns square of a number
def square(number):
    return number * number

# apply square() function to each item of the numbers list
squared_numbers_iterator = map(square, numbers)

# converting to list
squared_numbers = list(squared_numbers_iterator)
print(squared_numbers)

# Output: [4, 16, 36, 64, 100]
[4, 16, 36, 64, 100]

Python pow()

The pow() function returns the power of a number.

# positive x, positive y (x**y)
print(pow(2, 2))    # 4

# negative x, positive y
print(pow(-2, 2))    # 4  

# positive x, negative y
print(pow(2, -2))    # 0.25

# negative x, negative y
print(pow(-2, -2))    # 0.25
4
4
0.25
0.25

Python reversed()

The reversed() function returns the reversed iterator of the given sequence.

# for string
seq_string = 'Python'
print(list(reversed(seq_string)))

# for tuple
seq_tuple = ('P', 'y', 't', 'h', 'o', 'n')
print(list(reversed(seq_tuple)))

# for range
seq_range = range(5, 9)
print(list(reversed(seq_range)))

# for list
seq_list = [1, 2, 4, 3, 5]
print(list(reversed(seq_list)))
['n', 'o', 'h', 't', 'y', 'P']
['n', 'o', 'h', 't', 'y', 'P']
[8, 7, 6, 5]
[5, 3, 4, 2, 1]

Python round()

The round() function returns a floating-point number rounded to the specified number of decimals.

number = 13.46

# round the number
rounded_number = round(number)
print(rounded_number)

# Output: 13
13

Python sorted()

The sorted() function sorts the elements of a given iterable in a specific order (ascending or descending) and returns it as a list.

numbers = [4, 2, 12, 8]

sorted_numbers = sorted(numbers)
print(sorted_numbers)

# Output: [2, 4, 8, 12]
[2, 4, 8, 12]

Python zip()

The zip() function takes iterables (can be zero or more), aggregates them in a tuple, and returns it.

languages = ['Java', 'Python', 'JavaScript']
versions = [14, 3, 6]

result = zip(languages, versions)
print(list(result))
[('Java', 14), ('Python', 3), ('JavaScript', 6)]

Note: Find more on Built-in Function

 
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