[Python tutorial] 19. Built-in Function

abs(n)

Returns the absolute value of a number

x = abs(-7.25)

all(iterable)

Returns True if all items in an iterable object are true

mylist = [True, True, True]
x = all(mylist)

any(iterable)

Returns True if any item in an iterable object is true

mylist = [False, True, False]
x = any(mylist)

ascii(object)

Returns a readable version of an object. Replaces none-ascii characters with escape character

x = ascii("My name is Ståle")

bin(n)

Returns the binary version of a number

x = bin(36)

bool(object)

Returns the boolean value of the specified object

x = bool(1)

bytearray(x, encoding, error)

Returns an array of bytes

x = bytearray(4)

bytes(x, encoding, error)

Returns a bytes object

x = bytes(4)

callable(object)

Returns True if the specified object is callable, otherwise False

def x():
  a = 5
print(callable(x))

chr(number)

Returns a character from the specified Unicode code.

x = chr(97)

classmethod()

Converts a method into a class method

compile(source, filename, mode, flag, dont_inherit, optimize)

Returns the specified source as an object, ready to be executed

x = compile('print(55)', 'test', 'eval')
exec(x)

complex(real, imaginary)

Returns a complex number

x = complex(3, 5)

delattr(object, attribute)

Deletes the specified attribute (property or method) from the specified object

class Person:
  name = "John"
  age = 36
  country = "Norway"
delattr(Person, 'age')

dict(keyword arguments)

Returns a dictionary (Array)

x = dict(name = "John", age = 36, country = "Norway")

dir(object)

Returns a list of the specified object's properties and methods

class Person:
  name = "John"
  age = 36
  country = "Norway"
print(dir(Person))

divmod(dividend, divisor)

Returns the quotient and the remainder when argument1 is divided by argument2

x = divmod(5, 2)

enumerate(iterable, start)

Takes a collection (e.g. a tuple) and returns it as an enumerate object

x = ('apple', 'banana', 'cherry')
y = enumerate(x)

eval(expression, globals, locals)

Evaluates and executes an expression

x = 'print(55)'
eval(x)

exec(object, globals, locals)

Executes the specified code (or object)

x = 'name = "John"\nprint(name)'
exec(x)

filter(function, iterable)

Use a filter function to exclude items in an iterable object

ages = [5, 12, 17, 18, 24, 32]
def myFunc(x):
  if x < 18:
return False
  else:
    return True
adults = filter(myFunc, ages)
for x in adults:
  print(x)

float(value)

Returns a floating point number

x = float(3)

format(value, format)

Formats a specified value

x = format(0.5, '%')

frozenset(iterable)

Returns a frozenset object

mylist = ['apple', 'banana', 'cherry']
x = frozenset(mylist)

getattr(object, attribute, default)

Returns the value of the specified attribute (property or method)

class Person:
  name = "John"
  age = 36
  country = "Norway"
x = getattr(Person, 'age')

globals()

Returns the current global symbol table as a dictionary

x = globals()
print(x)

hasattr(object, attribute)

Returns True if the specified object has the specified attribute (property/method)

class Person:
  name = "John"
  age = 36
  country = "Norway"
x = hasattr(Person, 'age')

hash()

Returns the hash value of a specified object

help()

Executes the built-in help system

hex(number)

Converts a number into a hexadecimal value

x = hex(255)

id(object)

Returns the id of an object

x = ('apple', 'banana', 'cherry')
y = id(x)

input(prompt)

Allowing user input

print('Enter your name:')
x = input()
print('Hello, ' + x)

int(value, base)

Returns an integer number

x = int(3.5)

isinstance(object, type)

Returns True if a specified object is an instance of a specified object

x = isinstance(5, int)

issubclass(object, subclass)

Returns True if a specified class is a subclass of a specified object

class myAge:
  age = 36
class myObj(myAge):
  name = "John"
  age = myAge
x = issubclass(myObj, myAge)

iter(object, sentinel)

Returns an iterator object

x = iter(["apple", "banana", "cherry"])
print(next(x))
print(next(x))
print(next(x))

len(object)

Returns the length of an object

mylist = ["apple", "banana", "cherry"]
x = len(mylist)

list(iterable)

Returns a list

x = list(('apple', 'banana', 'cherry'))

locals()

Returns an updated dictionary of the current local symbol table

x = locals()
print(x)

map(function, iterables)

Returns the specified iterator with the specified function applied to each item

def myfunc(n):
  return len(n)
x = map(myfunc, ('apple', 'banana', 'cherry'))

max(n1, n2, n3, ...)

Returns the largest item in an iterable

x = max(5, 10)

memoryview(obj)

Returns a memory view object

x = memoryview(b"Hello")
print(x)

#return the Unicode of the 
first character
print(x[0])

#return the Unicode of the second 
character
print(x[1])

min(n1, n2, n3, ...)

Returns the smallest item in an iterable

x = min(5, 10)

next(iterable, default)

Returns the next item in an iterable

mylist = iter(["apple", "banana", "cherry"])
x = next(mylist)
print(x)
x = next(mylist)
print(x)
x = next(mylist)
print(x)

object()

Returns a new object

x = object()

oct(int)

Converts a number into an octal

x = oct(12)

open(file, mode)

Opens a file and returns a file object

f = open("demofile.txt", "r")
print(f.read())

ord(character)

Convert an integer representing the Unicode of the specified character

x = ord("h")

pow(x, y, z)

Returns the value of x to the power of y

x = pow(4, 3)

print(object(s), sep=separator, end=end, file=file, flush=flush)

Prints to the standard output device

print("Hello World")

property()

Gets, sets, deletes a property

range(start, stop, step)

Returns a sequence of numbers, starting from 0 and increments by 1 (by default)

x = range(6)
for n in x:
  print(n)

repr()

Returns a readable version of an object

reversed(sequence)

Returns a reversed iterator

alph = ["a", "b", "c", "d"]
ralph = reversed(alph)
for x in ralph:
print(x)

round(number, digits)

Rounds a numbers

x = round(5.76543, 2)
print(x)

set(iterable)

Returns a new set object

x = set(('apple', 'banana', 'cherry'))

setattr(object, attribute, value)

Sets an attribute (property/method) of an object

class Person:
  name = "John"
  age = 36
  country = "Norway"
setattr(Person, 'age', 40)

slice(start, end, step)

Returns a slice object

a = ("a", "b", "c", "d", "e", "f", "g", "h")
x = slice(2)
print(a[x])

sorted(iterable, key=key, reverse=reverse)

Returns a sorted list

a = ("b", "g", "a", "d", "f", "c", "h", "e")
x = sorted(a)
print(x)

staticmethod()

Converts a method into a static method

str(object, encoding=encoding, errors=errors)

Returns a string object

x = str(3.5)

sum(iterable, start)

Sums the items of an iterator

a = (1, 2, 3, 4, 5)
x = sum(a)

super()

Returns an object that represents the parent class

class Parent:
  def __init__(self, txt):
    self.message = txt
  def printmessage(self):
    print(self.message)
class Child(Parent):
  def __init__(self, txt):
    super().__init__(txt)
x = Child("Hello, and welcome!")
x.printmessage()

tuple(iterable)

Returns a tuple

x = tuple(('apple', 'banana', 'cherry'))

type(object, bases, dict)

Returns the type of an object

a = ('apple', 'banana', 'cherry')
b = "Hello World"
c = 33

x = type(a)
y = type(b)
z = type(c)

vars(object)

Returns the __dict__ property of an object

class Person:
  name = "John"
  age = 36
  country = "norway"
x = vars(Person) 

zip(iterator1, iterator2, iterator3 ...)

Returns an iterator, from two or more iterators

a = ("John", "Charles", "Mike")
b = ("Jenny", "Christy", "Monica")
x = zip(a, b)