{JS vs PYTHON Syntax}

Simple Cheet sheet by Shijo Shaji

1

Whitespace / Blocks

2

Commenting

3

Printing to Terminal

5

Arithmetic Operators

4

Variables

6

Boolean

7

Logical Operators

8

If Conditionals

9

While Loops

11

Array/List

10

For Loops

12

Functions

13

Strings

14

Object / Dictionaries

15

TBD

17

TBD

16

TBD

18

TBD

# PRESENTING CODE

Whitespace / Blocks - JS

if (x == 2) {
  console.log("x must be 2")
} else {
  if (x == 3) {
    console.log("x must be 3")
  } else {
    console.log("x must be something else")
  }
}

Whitespace is Javascript has no meaning. Blocks of code are declared with braces { }. Indentation is used for readability.

if x == 2:
  print("x must be 2")
else:
  if x == 3:
    print("x must be 3")
  else:
    print("x must be something else")

# PRESENTING CODE

Whitespace / Blocks - Python

You can use space or tab. Without proper indentation, you will get an error

// Single Line Comment

# PRESENTING CODE

Commenting - JS

/*
 * Multiple line:
 *  Anything between here is a
comment- this 
can extend several lines*/

# Single Line Comment

# PRESENTING CODE

Commenting - Python

"""
Multiple Line comment
At this pointanything between triple quotes are comments
"""

// JAVASCRIPT

console.log("print this!")

# PRESENTING CODE

Printing to Terminal

# PYTHON

print("print this to terminal")

// JS Variables declaration

let x = "Hello there"
const y = "Good bye"

# PRESENTING CODE

Variables

# Python variables declaration

x = "Hello there"
y = "Good bye"

Arithmetic Operators

The arithmetic operators between Javascript and Python are identical — except for one.

Python is missing:

pre-decrement/ post-decrement,

pre-increment/ post-increment operators.

since Python treats all numbers as floats (decimal numbers), you can use the double division sign // to get an integer.

// Javascript users lowercase

let x = true;
let y = false;

# PRESENTING CODE

Boolean

#  Python users Uppercase

x = True;
y = False;

// Javascript

=== Strict equality
!== Strict inequality


// Example:

0 == "0"  // true
0 === "0" // false

0 == []   // true
0 === []  // false

0 == 0    // true
0 === 0   // true

# PRESENTING CODE

Boolean

The boolean operators between Javascript and Python are identical — except for two extra JS operators. Python is missing the strict equality/inequality operators.

// Javascript

!     //Logical inverse, not
&&    //Logical AND
||    //Logical OR

# PRESENTING CODE

Logical Operators

# Python

not    # Logical inverse, not
and    # Logical AND
or     # Logical OR

// Javascript

if (x == 10) {
  console.log("x is 10")
} else if (x == 20) {
  console.log("x is 20")
} else {
  console.log("x is something else")
}

# PRESENTING CODE

If Conditionals

# Python

if x == 10:
  print("x is 10")
elif x == 20:
  print("x is 20")
else:
  print("x is something else")

// Javascript

let x = 10
while (x >= 0) {
  console.log(x)
  x--
}
// output: 10 down to 0

# PRESENTING CODE

While Loops

# Python

x = 10
while x >= 0:
  print(x)
  x -= 1
# prints from 10 down to 0

// Javascript

for (let i = 0; i < 10; i++) {
  console.log(i)
}

// Output : 0-9

# PRESENTING CODE

For Loops

# Python

for i in range(10):
  print(i)   
  
# Prints 0-9

# we can iterate over types

a = [10, 20, 30]


for i in a:
  print(i)  # Print 10 20 30

# dictionary
b = {'x':5, 'y':15, 'z':0}


for i in b:
  print(i) # Print x y z (the keys of the dict)

// Javascript Creating Array

let a1 = new Array()   // Empty array
let a2 = new Array(10) // Array of 10 elements
let a3 = []            // Empty array
let a4 = [10, 20, 30]  // Array of 3 elements
let a5 = [1, 2, "b"]   // No problem

# PRESENTING CODE