Python

• Don't repeat any code! If you do that, there is something wrong. Don't dry (don't repeat yourself)

It is a Case-Sensitive language. Keep your variable lower case letters. No space, If you need, use _ .  Ex: my_language

print ('Hello World')

print(f"{kind} kilos ")     # kind is a variable which defined before.

name= input (' What is your name? ')

str: All input are str (default). You need to convert them int or float to make calculation

float

int

' ' ' 

You can write whatever you want here

' ' '

word= "Python and Mr.G"

print (word[0:4])  ==> Pyth    

 0 is P.

 4 is o. But the last one is excluded.

Examples:

print (word[2])     ==> t

print (word[-1])     ==> G

print (word[2:5])     ==> tho

print(word[1:-1])  ==> ython and Mr.

Function = Methods

message.upper()                   # to convert to uppercase

message.lower()                   # to convert to lowercase

message.title()                      # to capitalize the first letter of every word

message.find(‘p’)                 # returns the index of the first occurrence of p (or -1 if not found)

message.replace(‘p’, ‘q’)

Arithmetic Operations

+

-

*

/                   # returns a float

//                  # returns an int

%                # returns the remainder of division

**                # exponentiation - x ** y = x to the power of y

x=x+3      is same as           x+=3

x=x-3       is same as           x-=3

Import any module

If you want to import math module; just type import module_name

For Ex: 

import math

Then call function like   math.function_name  ex: math.floor (2.8)  => result is 2.

*search python3 math module on Google to see more 

IF STATEMENT

if                    # Don't forget to put : after if 

elif                 # it means   else if

else                # when it catches if; it goes out of if statement

# Feel free to use "and" & "or" & "and not" & "if not" to conditional usage. and&or must be lower case, not upper case!

# You can put another if in the if statement.

number = input ("put a number==> ")

b=int(number)

if b>300:

    print("number is bigger 300")

elif b<200 and b>100:

    print("number you entered is between 100 and 200")

else:

    print("nooooooopeee")

Note: if start:    is equal to    if start == True:

Comparison operators

a > b

a >= b (greater than or equal to)

a < b

a <= b

a == b (equals)

a != b (not equals) 

While LOOP 

It is a loop.

while

     break    # it breaks while loop. It means the code goes the end of the while loop. If you use break function in while you can use "while:True" as a statement. If you don't put break, it goes forever.

else             # else may be used for while loop as well!

for   LOOP 

It is a loop.

for a in (1,2,3):
    print(a)

for a in range (1,10):
    print(a)