The Python built-in functions are defined as the functions
whose functionality is pre-defined in Python. The python interpreter has
several functions that are always present for use. These functions are known as
Built-in Functions. There are several built-in functions in Python which are
listed below:
Python abs() Function
The python abs() function is used to return the absolute
value of a number. It takes only one argument, a number whose absolute value is
to be returned. The argument can be an integer and floating-point number. If
the argument is a complex number, then, abs() returns its magnitude.
Example
# integer number
integer = -20
print('Absolute value of -40 is:', abs(integer))
# floating
number
floating = -20.83
print('Absolute value of -40.83 is:', abs(floating))
Output:
Absolute value of -20 is: 20
Absolute value of -20.83 is: 20.83
Python all() Function
The python all() function accepts an iterable object (such
as list, dictionary, etc.). It returns true if all items in passed iterable are
true. Otherwise, it returns False. If the iterable object is empty, the all()
function returns True.
Example
# all values true
k = [1, 3, 4, 6]
print(all(k))
# all values false
k = [0, False]
print(all(k))
# one false value
k = [1, 3, 7, 0]
print(all(k))
# one true value
k = [0, False, 5]
print(all(k))
# empty iterable
k = []
print(all(k))
Output:
True
False
False
False
True
Python bin() Function
The python bin() function is used to return the binary
representation of a specified integer. A result always starts with the prefix
0b.
Example
x = 10
y = bin(x)
print (y)
Output:
0b1010
Python bool()
The python bool() converts a value to boolean(True or False)
using the standard truth testing procedure.
Example
test1 = []
print(test1,'is',bool(test1))
test1 = [0]
print(test1,'is',bool(test1))
test1 = 0.0
print(test1,'is',bool(test1))
test1 = None
print(test1,'is',bool(test1))
test1 = True
print(test1,'is',bool(test1))
test1 = 'Easy string'
print(test1,'is',bool(test1))
Output:
[] is False
[0] is True
0.0 is False
None is False
True is True
Easy string is True
Python bytes()
The python bytes() in Python is used for returning a bytes
object. It is an immutable version of the bytearray() function.
It can create empty bytes object of the specified size.
Example
string = "Hello World."
array = bytes(string, 'utf-8')
print(array)
Output:
b ' Hello World.'
Python callable() Function
A python callable() function in Python is something that can
be called. This built-in function checks and returns true if the object passed
appears to be callable, otherwise false.
Example
x = 8
print(callable(x))
Output:
False
Python compile() Function
The python compile() function takes source code as input and
returns a code object which can later be executed by exec() function.
Syntax:
compile(source, filename, mode, flags=0, dont_inherit=False,
optimize=-1)
Parameters:
Source – It can be a normal string, a byte string, or an AST
object
Filename -This is the file from which the code was read. If
it wasn’t read from a file, you can give a name yourself.
Mode – Mode can be exec, eval or single.
eval –
If the sorce is a single expression.
exec –
It can take a block of a code that has Python statements, class and functions
and so on.
single
– It is used if consists of a single interactive statement
Flags (optional) and dont_inherit (optional) – Default
value=0. It takes care that which future statements affect the compilation of
the source.
Optimize (optional) – It tells optimization level of
compiler. Default value -1.
Example
# Creating sample sourcecode to multiply two variables
# x and y.
srcCode = 'x = 10\ny = 20\nmul = x * y\nprint("mul
=", mul)'
# Converting above source code to an executable
execCode = compile(srcCode, 'mulstring', 'exec')
# Running the executable code.
exec(execCode)
Output:
mul = 200
Python exec() Function
The python exec() function is used for the dynamic execution
of Python program which can either be a string or object code and it accepts
large blocks of code, unlike the eval() function which only accepts a single
expression.
Example
x = 8
exec('print(x==8)')
exec('print(x+4)')
Output:
True
12
Python sum() Function
As the name says, python sum() function is used to get the
sum of numbers of an iterable, i.e., list.
Example
s = sum([1, 2,4 ])
print(s)
s = sum([1, 2, 4], 10)
print(s)
Output:
7
17
Python any() Function
The python any() function returns true if any item in an
iterable is true. Otherwise, it returns False.
Example
l = [4, 3, 2, 0]
print(any(l))
l = [0, False]
print(any(l))
l = [0, False, 5]
print(any(l))
l = []
print(any(l))
Output:
True
False
True
False
Python ascii() Function
The python ascii() function returns a string containing a
printable representation of an object and escapes the non-ASCII characters in
the string using \x, \u or \U escapes.
Example
normalText = 'Python is interesting'
print(ascii(normalText))
otherText = 'Pythön is interesting'
print(ascii(otherText))
print('Pyth\xf6n is interesting')
Output:
'Python is interesting'
'Pyth\xf6n is interesting'
Pythön is interesting
Python bytearray()
The python bytearray() returns a bytearray object and can
convert objects into bytearray objects, or create an empty bytearray object of
the specified size.
Example
string = "Python is a programming language."
# string with encoding 'utf-8'
arr = bytearray(string, 'utf-8')
print(arr)
Output:
bytearray(b'Python is a programming language.')
Python eval() Function
The python eval() function parses the expression passed to
it and runs python expression(code) within the program.
Example
x = 8
print(eval('x + 1'))
Output:
9
Python float()
The python float() function returns a floating-point number
from a number or string.
Example
# for integers
print(float(9))
# for floats
print(float(8.19))
# for string floats
print(float("-24.27"))
# for string floats with whitespaces
print(float("
-17.19\n"))
# string float error
print(float("xyz"))
Output:
9.0
8.19
-24.27
-17.19
ValueError: could not convert string to float: 'xyz'
Python format() Function
The python format() function returns a formatted
representation of the given value.
Example
# d, f and b are a type
# integer
print(format(123, "d"))
# float arguments
print(format(123.4567898, "f"))
# binary format
print(format(12, "b"))
Output:
123
123.456790
1100
Python frozenset()
The python frozenset() function returns an immutable
frozenset object initialized with elements from the given iterable.
Example
# tuple of letters
letters = ('m', 'r', 'o', 't', 's')
fSet = frozenset(letters)
print('Frozen set is:', fSet)
print('Empty frozen set is:', frozenset())
Output:
Frozen set is: frozenset({'o', 'm', 's', 'r', 't'})
Empty frozen set is: frozenset()
Python getattr() Function
The python getattr() function returns the value of a named
attribute of an object. If it is not found, it returns the default value.
Example
class Details:
age = 22
name =
"Phill"
details = Details()
print('The age is:', getattr(details, "age"))
print('The age is:', details.age)
Output:
The age is: 22
The age is: 22
Python globals() Function
globals() function in Python returns the dictionary of
current global symbol table.
Symbol table: Symbol table is a data structure which
contains all necessary information about the program. These include variable
names, methods, classes, etc.
Global symbol table stores all information related to the
global scope of the program, and is accessed in Python using globals() method.
The functions, variables which are not associated with any
class or function are stored in global scope.
Syntax: globals()
Parameters: No parameters required.
Example
# global variable
a = 5
def func():
c = 10
d = c + a
# Calling
globals()
globals()['a'] = d
print (d)
# Driver Code
func()
Output:
15
Python hasattr() Function
The python any() function returns true if any item in an
iterable is true, otherwise it returns False.
Example
l = [4, 3, 2, 0]
print(any(l))
l = [0, False]
print(any(l))
l = [0, False, 5]
print(any(l))
l = []
print(any(l))
Output:
True
False
True
False
Python iter() Function
The python iter() function is used to return an iterator
object. It creates an object which can be iterated one element at a time.
Example
# list of numbers
list = [1,2,3,4,5]
listIter = iter(list)
# prints '1'
print(next(listIter))
# prints '2'
print(next(listIter))
# prints '3'
print(next(listIter))
# prints '4'
print(next(listIter))
# prints '5'
print(next(listIter))
Output:
1
2
3
4
5
Python len() Function
The python len() function is used to return the length (the
number of items) of an object.
Example
strA = 'Python'
print(len(strA))
Output:
6
Python list()
The python list() creates a list in python.
Example
# empty list
print(list())
# string
String = 'abcde'
print(list(String))
# tuple
Tuple = (1,2,3,4,5)
print(list(Tuple))
# list
List = [1,2,3,4,5]
print(list(List))
Output:
[]
['a', 'b', 'c', 'd', 'e']
[1,2,3,4,5]
[1,2,3,4,5]
Python locals() Function
locals() function in Python returns the dictionary of
current local symbol table.
Symbol table: It is a data structure created by compiler for
which is used to store all information needed to execute a program.
Local symbol Table: This symbol table stores all information
which needed to local scope of the program and this information is accessed
using python built in function locals().
Syntax : locals()
Parameters: This function does not takes any input parameter.
Return Type : This returns the information stored in local
symbol table.
Example:
# here no local variable is present
def demo1():
print("Here
no local variable is present : ",
locals())
# here local variables are present
def demo2():
name = "Ankit"
print("Here
local variables are present : ", locals())
# driver code
demo1()
demo2()
Output:
Here no local variable
is present : {}
Here local variables are present : {'name': 'Ankit'}
Python map() Function
The python map() function is used to return a list of
results after applying a given function to each item of an iterable(list, tuple
etc.).
Example
def calculateAddition(n):
return n+n
numbers = (1, 2, 3, 4)
result = map(calculateAddition, numbers)
print(result)
# converting map object to set
numbersAddition = set(result)
print(numbersAddition)
Output:
<map object at 0x7fb04a6bec18>
{8, 2, 4, 6}
Python memoryview() Function
The python memoryview() function returns a memoryview object
of the given argument.
Example
#A random bytearray
randomByteArray = bytearray('ABC', 'utf-8')
mv = memoryview(randomByteArray)
# access the memory view's zeroth index
print(mv[0])
# It create byte from memory view
print(bytes(mv[0:2]))
# It create list from memory view
print(list(mv[0:3]))
Output:
65
b'AB'
[65, 66, 67]
Python object()
The python object() returns an empty object. It is a base
for all the classes and holds the built-in properties and methods which are
default for all the classes.
Example
python = object()
print(type(python))
print(dir(python))
Output:
<class 'object'>
['__class__', '__delattr__', '__dir__', '__doc__', '__eq__',
'__format__', '__ge__',
'__getattribute__', '__gt__', '__hash__', '__init__',
'__le__', '__lt__', '__ne__',
'__new__', '__reduce__', '__reduce_ex__', '__repr__',
'__setattr__', '__sizeof__',
'__str__', '__subclasshook__']
Python open() Function
The python open() function opens the file and returns a
corresponding file object.
Sytax: open(file, mode='r', buffering=-1, encoding=None,
errors=None, newline=None, closefd=True, opener=None)
Parameters
file - path-like object (representing a file system path)
giving the pathname
mode (optional) - mode while opening a file. If not
provided, it defaults to 'r' (open for reading in text mode). Available file
modes are:
Modes :
'r' : Open a file for reading. (default)
'w' : Open a
file for writing. Creates a new file if it does not exist or truncates the file
if it exists.
'x' : Open a
file for exclusive creation. If the file already exists, the operation fails.
'a' : Open
for appending at the end of the file without truncating it. Creates a new file
if it does not exist.
't' : Open
in text mode. (default)
'b' : Open in
binary mode.
'+' : Open a
file for updating (reading and writing)
buffering (optional) - used for setting buffering policy
encoding (optional) - name of the encoding to encode or
decode the file
errors (optional) - string specifying how to handle
encoding/decoding errors
newline (optional) - how newlines mode works (available
values: None, ' ', '\n', 'r', and '\r\n'
closefd (optional) - must be True (default) if given
otherwise an exception will be raised
opener (optional) - a custom opener; must return an open
file descriptor
Example
# opens python.text file of the current directory
f = open("python.txt")
# specifying full path
f = open("C:/Python33/README.txt")
Output:
Since the mode is omitted, the file is opened in 'r' mode;
opens for reading.
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