8.3: Built-In Functions

Built-in functions are loaded into memory when you start Python, and are available to use without having to import them

A list of built-in functions can be found at docs.python.org.

We will look at some common built-in functions.

float()

• convert string or integer to a floating decimal number

a="1"
print(a)
print(type(a))
a=float(a)
print(10*"*")
print(a)
print(type(a))

Hello world!

 

input()

• Allows you to input a value
• All inputs are strings

a=input("Enter a number")
print(a)
print(type(a))
b=input("write a sentence")
print(b)

Enter a number 3

 

int()

• Converts a string or float to an integer

a="1"
print(a)
print(type(a))
a=int(a)
print(10*"*")
print(a)
print(type(a))

Hello world!

 

len()

• returns length of an object

print(len('hello world'))
print(len("123456789"))

        hello world
      

 

Math Functions

abs()

• Returns absolute value of a number

print(abs(-34.5))
print(abs(34.5))

        hello world
      

pow(base,exponent)

• returns base to the power of the exponent

print(pow(2,3))
print(pow(10,3))

        hello world
      

round()

• Rounds up or down a number

print(round(33.545))
print(round(33.545,1))
print(round(33.545,2))
print(round(33.545,-1))

Hello world!

max()

• gives largest item of an iterable, or smallest of two or more values

  print(max([2,8,4]))
  print(max(["alpha","gamma","beta"]))

  Hello world!

   

min()

• gives smallest item of an iterable, or smallest of two or more values

print(min([2,8,4]))
print(min(["alpha","gamma","beta"]))

Hello world!

 

print()

• strings must be in parenthesis
• \n gives new line
• \t is tab
• multiple format options

Note: Print Formatting

Note, there are multiple ways you can format the output of the print statement and because this is very important we have a section devoted purely to print formatting.

str()

• converts an integer or floating decimal to a string

type()

• returns the type of an object