Common Python Built‑in Functions: 68 Frequently Used Examples

Python is a popular programming language with a powerful standard library; this article presents 68 frequently used built‑in functions, grouped by data type, and supplies clear code examples for each.

Numeric functions such as abs(), divmod(), pow() and round() demonstrate how to obtain absolute values, quotient‑remainder pairs, exponentiation, and rounding:

a = -5
print(abs(a))  # 5

a, b = 10, 3
print(divmod(a, b))  # (3, 1)

print(pow(2, 3))  # 8

a = 2.8
print(round(a))  # 3

String functions include chr(), ord(), len(), str(), capitalize(), lower(), upper(), swapcase(), title(), strip(), replace(), split() and join(), illustrating character conversion, length retrieval, case manipulation, whitespace trimming, substitution, splitting, and joining operations.

print(chr(97))          # 'a'
print(ord('a'))        # 97
s = 'hello world'
print(len(s))          # 11
print(str(123))        # '123'
print(s.capitalize())   # 'Hello world'
print(s.upper())        # 'HELLO WORLD'
print(s.swapcase())    # 'hELLO wORLD'
print(s.title())       # 'Hello World'
print(s.strip())       # 'hello world'
print(s.replace('l','i')) # 'heiioworid'
print('hello,world'.split(',')) # ['hello', 'world']
print('-'.join(['hello','world'])) # 'hello-world'

List functions such as len(), max(), min(), sum(), sorted(), reversed(), list(), append(), insert(), remove(), pop(), extend(), index(), and count() show how to query size, find extrema, aggregate, reorder, convert, and modify list contents.

lst = [1, 2, 3, 4, 5]
print(len(lst))   # 5
print(max(lst))   # 5
print(min(lst))   # 1
print(sum(lst))    # 15
print(sorted([3,1,4,2,5])) # [1, 2, 3, 4, 5]
print(list(reversed(lst))) # [5, 4, 3, 2, 1]
lst.append(6)
print(lst)        # [1,2,3,4,5,6]
lst.insert(1, 0)
print(lst)        # [1,0,2,3,4,5,6]
lst.remove(3)
print(lst)        # [1,0,2,4,5,6]
print(lst.pop())  # 6

Dictionary functions like len(), keys(), values(), items(), get(), pop(), and update() illustrate how to inspect size, retrieve keys/values, safely access entries, delete items, and merge mappings.

d = {'a':1, 'b':2, 'c':3}
print(len(d))          # 3
print(d.keys())        # dict_keys(['a','b','c'])
print(d.values())      # dict_values([1,2,3])
print(d.items())       # dict_items([('a',1),('b',2),('c',3)])
print(d.get('a'))      # 1
print(d.get('d',0))    # 0
print(d.pop('b'))      # 2
print(d)                # {'a':1,'c':3}
d1 = {'a':1,'b':2}
d2 = {'b':3,'c':4}
d1.update(d2)
print(d1)               # {'a':1,'b':3,'c':4}

Tuple functions ( len(), max(), min(), tuple()) demonstrate length, extremum retrieval, and conversion from other iterables.

t = (1,2,3)
print(len(t))   # 3
print(max(t))   # 3
print(min(t))   # 1
print(tuple([4,5,6])) # (4,5,6)

Set functions ( len(), max(), min(), set(), add(), remove()) cover size, extremum, creation, addition, and removal of elements.

s = {1,2,3}
print(len(s))   # 3
print(max(s))   # 3
print(min(s))   # 1
print(set([4,5])) # {4,5}
s.add(4)
print(s)        # {1,2,3,4}
s.remove(2)
print(s)        # {1,3,4}

File‑handling functions ( open(), close(), read(), write()) show basic file I/O operations.

f = open('test.txt','r')
content = f.read()
print(content)
f.close()

f = open('test.txt','w')
f.write('hello world
')
f.close()

Other useful functions such as isinstance(), range(), zip(), map(), filter(), reduce(), and another round() example illustrate type checking, sequence generation, aggregation, and functional programming utilities.

print(isinstance(10,int))   # True
print(list(range(5)))       # [0,1,2,3,4]
print(list(zip([1,2,3],['a','b','c']))) # [(1,'a'),(2,'b'),(3,'c')]
print(list(map(lambda x: x*2, [1,2,3]))) # [2,4,6]
print(list(filter(lambda x: x%2==0, [1,2,3,4,5]))) # [2,4]
from functools import reduce
print(reduce(lambda x,y: x*y, [1,2,3])) # 6
print(round(2.8)) # 3

In summary, these 68 built‑in functions provide convenient operations for common data types, helping developers write clearer and more efficient Python code.