# Built in Functions in Python

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In this post, we will list most of common Built-In Python functions that you should to know as a beginner

## Python Built-In Functions

• Syntax: abs()

Definition and Usage: It returns the absolute value of the specified number.

``````number = -999
print (abs (number))``````
• Syntax: dir()

Definition and UsageIt returns list of the attributes and methods of any object.

``````class Student:
def __init__(self, name, age, id, grades):
self.name = name
self.age = age
self.id = id

def talk(self):
print ('My name is:' , self.name)

std1 = Student('Alaa' , 21, 'xx00', [95, 98, 99])
std2 = Student('Reemaz', 19, 'xx01', 86)

print (dir(std2))``````
• Syntax: round()

Definition and UsageIt returns a floating point number that is a rounded version of the specified number, with the specified number of decimals.

``````number = 3.673
print (round(number))
#Or
number = 3.673
print (round(number , 2))``````
• Syntax: pow()

Definition and UsageIt returns the value of x to the power of y.

``````number = 3
print (pow (number , 2))
#Or
print (pow(3,2))
``````
• Syntax: max()

Definition and UsageIt returns the largest of the input values.

``````numbers = 300, 600, 786, 1000, 267
print (max)(numbers)
#Or
print (max(300, 600, 786, 1000, 276))
``````
• Syntax: min()

Definition and UsageIt returns the smallest of the input values.

``````numbers = 300, 600, 786, 1000, 267
print (min)(numbers)
#Or
print (min(300, 600, 786, 1000, 276, 1000, 267))``````
• Syntax: sum()

Definition and UsageIt calculates the total of all numerical values.

``````numbers = 300, 600, 786, 1000, 267
print (sum(numbers))``````
• Syntax: len()

Definition and UsageThe number of elements stored in the object is never calculated, so len helps provide the number of elements.

``````the_String =  'abcdefghijklmnopgrstuvwxyz'
the_list = [1, 2, 2, 3]
the_tuple = (1,2, 3)
print (len(the_String))
print (len(the_list))
print (len(the_tuple))``````
• Syntax: Format()

Definition and Usage

It formats the specified value(s) and insert them inside the string's placeholder

Note: The placeholder is defined using curly brackets: {}

``````first_name = 'Alaa'
last_name = 'Salman'
age = 19
print ('my name is {} {}, and iam {} years old'.format (first_name,last_name, age))

#Or by the index

first_name = 'Alaa'
last_name = 'Salman'
age = 19
print ('my name is {1}, and my last name is {0}, and i am {2} years old'.format (last_name, first_name,age))
``````
• Syntax: filter()

Definition and UsageIt filters the given sequence with the help of a function that tests each element in the sequence to be true or not.

``````ages = [30, 9, 15, 22, 17, 44, 26, 5]
def filtered_ages (ages):
return ages >= 18
print(list(filter(filtered_ages, ages)))
``````
• Syntax: map()

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

``````numbers = [ 5, 10, 20, 25, 50 ]
def square (num):
return num ** 2
print (list(map(square, numbers)))``````
• Syntax: reverse()

Definition and UsageIt reverses the elements of the list.

``````names = [ 'alaa',  'Reemaz',  'Taif' ]
names.reverse()
print (names)``````
• Syntax: super()

Definition and Usage:  It returns an object that represents the parent class

``````class Person:
def __init__(self, first_name, surname, tel ):
self.first_name = first_name
self.surname = surname
self.tel = tel

def full_name(self):
return self.first_name + " " + self.surname

class Employee(Person):
def __init__(self,first_name, surname, tel, salary):
super().__init__(first_name, surname, tel)
self.salary = salary

def give_raise (self, amount):
self.salary = self.salary + amount

emp1 = Employee(1700, 'Ali', 'Ahmed', '+96656xxxxxxx')``````