We have talked about Functions in Python. In that tutorial of Python Functions, we discussed user-defined functions in Python. But that isn\u2019t all, a list of Python built-in functions that we can toy around with.<\/p>\n
In this tutorial on Built-in functions in Python, we will see each of those; we have 67 of those in Python 3.6 with their Python Syntax and examples.<\/p>\n
So, let’s start Python Built-In Functions.<\/p>\n
Python ships with many ready-made helpers called built-in functions. You do not import them; they sit in memory the moment the interpreter starts. Names like len, sum, and print pop up in almost every script because they solve everyday chores quickly.<\/p>\n
When you learn what each built-in function does, your code becomes shorter and more expressive. A one-line sum(numbers) tells more than a loop that adds by hand. Mastering this toolbox is the first step toward writing Pythonic programs that rank high in clarity and performance.<\/p>\n
The abs() in python is one of the most popular Python built-in functions, which returns the absolute value of a number.<\/p>\n
A negative value\u2019s absolute is that value is positive.<\/p>\n
>>> abs(-7)<\/pre>\nOutput<\/strong><\/p>\n
7<\/div>\n>>> abs(7)<\/pre>\nOutput<\/strong><\/p>\n
7<\/div>\n>>> abs(0)<\/pre>\n2. all() in python<\/h4>\n
The all() function in Python takes a container as an argument. This built-in function returns True if all values in a Python iterable have a Boolean value of True.<\/p>\n
An empty value has a Boolean value of False.<\/p>\n
>>> all({'*','',''})<\/pre>\nOutput<\/strong><\/p>\n
False<\/div>\n>>> all([' ',' ',' '])<\/pre>\nOutput<\/strong><\/p>\n
True<\/div>\n3. any() in python<\/h4>\n
Like all(), it takes one argument and returns True if, even one value in the iterable has a Boolean value of True.<\/p>\n
>>> any((1,0,0))<\/pre>\nOutput<\/strong><\/p>\n
True<\/div>\n>>> any((0,0,0))<\/pre>\nOutput<\/strong><\/p>\n
False<\/div>\n4.\u00a0 ascii() in python<\/h4>\n
Python built-in functions must return a printable representation of a Python object (like a string or a Python list).<\/p>\n
Let\u2019s take a Romanian character.<\/p>\n
>>> ascii('\u0219')<\/pre>\nOutput<\/strong><\/p>\n
“‘\\\\u0219′”<\/div>\nSince this was a non-ASCII character in Python, the interpreter added a backslash (\\) and escaped it using another backslash.<\/p>\n
>>> ascii('u\u0219or')<\/pre>\nOutput<\/strong><\/p>\n
“‘u\\\\u0219or'”<\/div>\nLet\u2019s apply it to a list.<\/p>\n
>>> ascii(['s','\u0219'])<\/pre>\nOutput<\/strong><\/p>\n
“[‘s’, ‘\\\\u0219’]”<\/div>\n5. bin() in python<\/h4>\n
The bin() function in Python converts an integer to a binary string. We have seen this and other functions in our article on Python Numbers.<\/p>\n
>>> bin(7)<\/pre>\nOutput<\/strong><\/p>\n
‘0b111’<\/div>\nWe can\u2019t apply it on floats, though.<\/p>\n
>>> bin(7.0)<\/pre>\nOutput<\/strong><\/p>\n
\nTraceback (most recent call last):File “<pyshell#20>”, line 1, in <module><\/p>\n
bin(7.0)<\/p>\n
TypeError: ‘float’ object cannot be interpreted as an integer<\/p>\n<\/div>\n
6. bool() in python<\/h4>\n
The bool() function in Python converts a value to a Boolean.<\/p>\n
>>> bool(0.5)<\/pre>\nOutput<\/strong><\/p>\n
True<\/div>\n>>> bool('')<\/pre>\nOutput<\/strong><\/p>\n
False<\/div>\n>>> bool(True)<\/pre>\nOutput<\/strong><\/p>\n
\nTrue<\/p>\n<\/div>\n
7. bytearray() in python<\/h4>\n
The bytearray() function returns a Python array of a given byte size.<\/p>\n
>>> a=bytearray(4)\r\n>>> a<\/pre>\nOutput<\/strong><\/p>\n
\nbytearray(b’\\x00\\x00\\x00\\x00′)<\/p>\n<\/div>\n
>>> a.append(1)\r\n>>> a<\/pre>\nOutput<\/strong><\/p>\n
\nbytearray(b’\\x00\\x00\\x00\\x00\\x01′)<\/p>\n<\/div>\n
>>> a[0]=1\r\n>>> a<\/pre>\nOutput<\/strong><\/p>\n
\nbytearray(b’\\x01\\x00\\x00\\x00\\x01′)<\/p>\n<\/div>\n
>>> a[0]<\/pre>\nOutput<\/strong><\/p>\n
\n1<\/p>\n<\/div>\n
Let\u2019s do this on a list.<\/p>\n
>>> bytearray([1,2,3,4])<\/pre>\nOutput<\/strong><\/p>\n
\nbytearray(b’\\x01\\x02\\x03\\x04′)<\/p>\n<\/div>\n
8. bytes() in Python<\/h4>\n
The bytes() function in Python returns an immutable bytes object.<\/p>\n
>>> bytes(5)<\/pre>\nOutput<\/strong><\/p>\n
\nb’\\x00\\x00\\x00\\x00\\x00′<\/p>\n<\/div>\n
>>> bytes([1,2,3,4,5])<\/pre>\nOutput<\/strong><\/p>\n
\nb’\\x01\\x02\\x03\\x04\\x05′<\/p>\n<\/div>\n
>>> bytes('hello','utf-8')<\/pre>\nOutput<\/strong><\/p>\n
\nb’hello’Here, utf-8 is the encoding.<\/p>\n<\/div>\n
Both bytes() and bytearray() deal with raw data, but bytearray() is mutable, while bytes() is immutable.<\/p>\n
>>> a=bytes([1,2,3,4,5])\r\n>>> a<\/pre>\nOutput<\/strong><\/p>\n
\nb’\\x01\\x02\\x03\\x04\\x05′<\/p>\n<\/div>\n
>>> a[4]=<\/pre>\nOutput<\/strong><\/p>\n
\n3Traceback (most recent call last):<\/p>\n
File “<pyshell#46>”, line 1, in <module><\/p>\n
a[4]=3<\/p>\n
TypeError: ‘bytes’ object does not support item assignment<\/p>\n<\/div>\n
Let\u2019s try this on bytearray().<\/p>\n
>>> a=bytearray([1,2,3,4,5])\r\n>>> a<\/pre>\nOutput<\/strong><\/p>\n
\nbytearray(b’\\x01\\x02\\x03\\x04\\x05′)<\/p>\n<\/div>\n
>>> a[4]=3\r\n>>> a<\/pre>\nOutput<\/strong><\/p>\n
\nbytearray(b’\\x01\\x02\\x03\\x04\\x03′)<\/p>\n<\/div>\n
9. callable() in Python<\/h4>\n
The callable() function in Python tells us if an object can be called.<\/p>\n
>>> callable([1,2,3])<\/pre>\nOutput<\/strong><\/p>\n
\nFalse<\/p>\n<\/div>\n
>>> callable(callable)<\/pre>\nOutput<\/strong><\/p>\n
\nTrue<\/p>\n<\/div>\n
>>> callable(False)<\/pre>\nOutput<\/strong><\/p>\n
\nFalse<\/p>\n<\/div>\n
>>> callable(list)<\/pre>\nOutput<\/strong><\/p>\n
\nTrue<\/p>\n<\/div>\n
A function is callable; a list is not. Even the callable() Python built-in function is callable.<\/p>\n
10. chr() in Python<\/h4>\n
chr() Built-in function returns the character in Python for an ASCII value.<\/p>\n
>>> chr(65)<\/pre>\nOutput<\/strong><\/p>\n
\n‘A’<\/p>\n<\/div>\n
>>> chr(97)<\/pre>\nOutput<\/strong><\/p>\n
\n‘a’<\/p>\n<\/div>\n
>>> chr(9)\r\n<\/pre>\nOutput<\/strong><\/p>\n
\n‘\\t’<\/p>\n<\/div>\n
>>> chr(48)<\/pre>\nOutput<\/strong><\/p>\n
\n‘0’<\/p>\n<\/div>\n
11. classmethod() in Python<\/h4>\n
The classmethod() function in Python returns a class method for a given method.<\/p>\n
>>> class fruit:\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 def sayhi(self):\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print(\"Hi, I'm a fruit\")\u00a0\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n>>> fruit.sayhi=classmethod(fruit.sayhi)\r\n>>> fruit.sayhi()<\/pre>\nOutput<\/strong><\/p>\n
\nHi, I’m a fruit<\/p>\n<\/div>\n
When we pass the method sayhi() as an argument to classmethod(), it converts it into a Python class method that belongs to the class.<\/p>\n
Then, we call it like we would call any static method in Python without an object.<\/p>\n
12. compile() in Python<\/h4>\n
The compile() function in Python returns a Python code object. We use Python in built function to convert a string code into object code.<\/p>\n
>>> exec(compile('a=5\\nb=7\\nprint(a+b)','','exec'))<\/pre>\nOutput<\/strong><\/p>\n
12<\/div>\nHere, \u2018exec\u2019 is the mode. The parameter before that is the filename for the file form which the code is read.<\/p>\n
Finally, we execute it using exec().<\/p>\n
13. complex() in Python<\/h4>\n
The complex() function in Python creates a complex number. We have seen this in our article on Python Numbers.<\/p>\n
>>> complex(3)<\/pre>\nOutput<\/strong><\/p>\n
\n(3+0j)<\/p>\n<\/div>\n
>>> complex(3.5)<\/pre>\nOutput<\/strong><\/p>\n
\n(3.5+0j)<\/p>\n<\/div>\n
>>> complex(3+5j)<\/pre>\nOutput<\/strong><\/p>\n
\n(3+5j)<\/p>\n<\/div>\n
14. delattr() in Python<\/h4>\n
The delattr() function in Python takes two arguments- a class, and an attribute in it. It deletes the attribute.<\/p>\n
>>> class fruit:\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 size=7\u00a0\u00a0\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n>>> orange=fruit()\r\n>>> orange.size<\/pre>\nOutput<\/strong><\/p>\n
\n7<\/p>\n<\/div>\n
>>> delattr(fruit,'size')\r\n>>> orange.size<\/pre>\nOutput<\/strong><\/p>\n
\nTraceback (most recent call last):File “<pyshell#95>”, line 1, in <module><\/p>\n
orange.size<\/p>\n
AttributeError: ‘fruit’ object has no attribute ‘size’<\/p>\n<\/div>\n
15. dict() in Python<\/h4>\n
The dict() function in Python, as we have seen it, creates a Python dictionary.<\/p>\n
>>> dict()<\/pre>\nOutput<\/strong><\/p>\n
\n{}<\/p>\n<\/div>\n
>>> dict([(1,2),(3,4)])<\/pre>\nOutput<\/strong><\/p>\n
\n{1: 2, 3: 4}<\/p>\n<\/div>\n
This was about dict() Python built-in function<\/p>\n
16. dir() in Python<\/h4>\n
The dir() function in Python returns an object\u2019s attributes.<\/p>\n
>>> class fruit:\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 size=7\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 shape='round'\r\n>>> orange=fruit()\r\n>>> dir(orange)<\/pre>\nOutput<\/strong><\/p>\n
[‘__class__’, ‘__delattr__’, ‘__dict__’, ‘__dir__’, ‘__doc__’, ‘__eq__’, ‘__format__’, ‘__ge__’, ‘__getattribute__’, ‘__gt__’, ‘__hash__’, ‘__init__’, ‘__init_subclass__’, ‘__le__’, ‘__lt__’, ‘__module__’, ‘__ne__’, ‘__new__’, ‘__reduce__’, ‘__reduce_ex__’, ‘__repr__’, ‘__setattr__’, ‘__sizeof__’, ‘__str__’, ‘__subclasshook__’, ‘__weakref__’, ‘shape’, ‘size’]<\/div>\n17. divmod() in Python<\/h4>\n
divmod() is a built-in function, takes two parameters, and returns a tuple of their quotient and remainder.<\/p>\n
In other words, it returns the floor division and the modulus of the two numbers.<\/p>\n
>>> divmod(3,7)<\/pre>\nOutput<\/strong><\/p>\n
\n(0, 3)<\/p>\n<\/div>\n
>>> divmod(7,3)<\/pre>\nOutput<\/strong><\/p>\n
(2, 1)<\/div>\nIf you encounter any doubt in Python Built-in Function, Please Comment.<\/p>\n
18. enumerate() in Python<\/h4>\n
This Python built-in function returns an enumerate object. In other words, it adds a counter to the iterable.<\/p>\n
>>> for i in enumerate(['a','b','c']):\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print(i)<\/pre>\nOutput<\/strong><\/p>\n
(0, ‘a’)
\n(1, ‘b’)
\n(2, ‘c’)<\/div>\n19. eval() in Python<\/h4>\n
The eval() Function in Python takes a string as an argument, which is parsed as an expression.<\/p>\n
>>> x=7\r\n>>> eval('x+7')<\/pre>\nOutput<\/strong><\/p>\n
\n14<\/p>\n<\/div>\n
>>> eval('x+(x%2)')<\/pre>\nOutput<\/strong><\/p>\n
\n8<\/p>\n<\/div>\n
20. exec() in Python<\/h4>\n
The exec() function runs Python code dynamically.<\/p>\n
>>> exec('a=2;b=3;print(a+b)')<\/pre>\nOutput<\/strong><\/p>\n
\n5<\/p>\n<\/div>\n
>>> exec(input(\"Enter your program\"))<\/pre>\nOutput<\/strong><\/p>\n
\nEnter your programprint(2+3)5<\/p>\n<\/div>\n
21. filter() in Python<\/h4>\n
Like we\u2019ve seen in python Lambda Expressios, filter() filters out the items for which the condition is True.<\/p>\n
>>> list(filter(lambda x:x%2==0,[1,2,0,False]))<\/pre>\nOutput<\/strong><\/p>\n
\n[2, 0, False]<\/p>\n<\/div>\n
22. float() in Python<\/h4>\n
This Python built-in function converts an int or a compatible value into a float.<\/p>\n
>>> float(2)<\/pre>\nOutput<\/strong><\/p>\n
\n2.0<\/p>\n<\/div>\n
>>> float('3')<\/pre>\nOutput<\/strong><\/p>\n
\n3.0<\/p>\n<\/div>\n
>>> float('3s')<\/pre>\nOutput<\/strong><\/p>\n
\nTraceback (most recent call last):File “<pyshell#136>”, line 1, in <module><\/p>\n
float(‘3s’)<\/p>\n
ValueError: could not convert string to float: ‘3s’<\/p>\n<\/div>\n
>>> float(False)<\/pre>\nOutput<\/strong><\/p>\n
\n0.0<\/p>\n<\/div>\n
>>> float(4.7)<\/pre>\nOutput<\/strong><\/p>\n
\n4.7<\/p>\n<\/div>\n
23. format() in Python<\/h4>\n
We have seen this Python built-in function,\u00a0<\/strong>one in our lesson on Python Strings.<\/p>\n
>>> a,b=2,3\r\n>>> print(\"a={0} and b={1}\".format(a,b))<\/pre>\nOutput<\/strong><\/p>\n
\na=2 and b=3<\/p>\n<\/div>\n
>>> print(\"a={a} and b={b}\".format(a=3,b=4))<\/pre>\nOutput<\/strong><\/p>\n
\na=3 and b=4<\/p>\n<\/div>\n
24. frozenset() in Python<\/h4>\n
frozenset() returns an immutable frozenset object.<\/p>\n
>>> frozenset((3,2,4))<\/pre>\nOutput<\/strong><\/p>\n
\nfrozenset({2, 3, 4})<\/p>\n<\/div>\n
25. getattr() in Python<\/h4>\n
getattr() returns the value of an object\u2019s attribute.<\/p>\n
>>> getattr(orange,'size')<\/pre>\nOutput<\/strong><\/p>\n
\n7<\/p>\n<\/div>\n
26. globals() in Python<\/h4>\n
This Python built-in functions, returns a dictionary of the current global symbol table.<\/p>\n
>>> globals()<\/pre>\nOutput<\/strong><\/p>\n
\n{‘__name__’: ‘__main__’, ‘__doc__’: None, ‘__package__’: None, ‘__loader__’: <class ‘_frozen_importlib.BuiltinImporter’>, ‘__spec__’: None, ‘__annotations__’: {}, ‘__builtins__’: <module ‘builtins’ (built-in)>, ‘fruit’: <class ‘__main__.fruit’>, ‘orange’: <__main__.fruit object at 0x05F937D0>, ‘a’: 2, ‘numbers’: [1, 2, 3], ‘i’: (2, 3), ‘x’: 7, ‘b’: 3}<\/p>\n<\/div>\n
27. hasattr() in Python<\/h4>\n
Like delattr() and getattr(), hasattr() Python built-in functions, returns True if the object has that attribute.<\/p>\n
>>> hasattr(orange,'size')<\/pre>\nOutput<\/strong><\/p>\n