Python for Frontend Engineers

Py thee on.

— William Shakespeare (meaning Python code turns you on) 😅

I tried to teach Python to myself for a week and now I’m able to read and understand Python code comfortably. This blog summarises my thought process while learning Python and comparing its syntax with Javascript at every step. I’ll keep updating it as and when I encounter new Pythonic stuff.

First and foremost, wear a gauntlet and snap a finger for semicolons, curly braces, and camelCase names to bite the dust.

console.log vs print

Javascript	Python
console.log(“Hello World!”);	print(“Hello World!”)
console.log(“Hello ” + “World!”);	print(“Hello ” + “World!”)
var greet = “Hello”; var who = “World!”; console.log(`${greet} ${who}`);	greet = “Hello” who = “World!” print(“{0} {1}”.format(greet, who))

Primitive Types

Javascript	Python
var name = “John Doe”;	name = “John Doe”
var age = 100;	age = 100
var isMale = true;	is_male = True

Utility Methods

Javascript	Python
“amit”.toUppercase();	“amit”.upper() # “amit”.upper().isupper()
“amit”.length;	len(“amit”)
“amit”.indexOf(“a”);	“amit”.index(“a”) // throws error if not found 😦
String(100);	str(100)
parseInt(100.300, 10);	int(100.300)
parseFloat(100.300, 10);	float(100.300)
Math.abs(-100);	abs(-100)
Math.pow(3, 2);	pow(3, 2)
Math.round(3.2);	round(3.2)
Math.floor(3.2);	floor(3.2)
Math.ceil(3.2);	ceil(3.2)
Math.sqrt(25);	sqrt(25)
NA (use Lodash)	max(4, 2)
NA (use Lodash)	min(4, 2)

User Input

Javascript	Python
var ans = prompt(“What’s up?”);	ans = input(“What’s up?”)

Arrays vs Lists

Javascript	Python
var arrStr = [“a”, “b”, “c”];	lst_str = [“a”, “b”, “c”]
arrStr[0]	lst_str[0]
arrStr[-1] // returns undefined	lst_str[-1] # returns “c”
NA	lst_str[1:] # returns [“b”, “c”]
NA	lst_str[1:2] # returns [“b”] ignores 3rd
NA	lst_str[:2] # returns [“a”, “b”] ignores 3rd
arrStr[1] = “d”;	lst_str[1] = “d”
arrStr.push(“d”);	lst_str.append(“d”)
arrStr.splice(1, 0, “f”);	lst_str.insert(1, “f”)
arrStr.indexOf(“b”);	lst_str.index(“b”)
NA	lst_str.count(“d”) # returns 2 occurrences
arrStr = arrStr.sort();	lst_str.sort()
arrStr.reverse();	lst_str.reverse()
var arrNum = [1, 2, 3];	lst_num = [1, 2, 3]
arrStr = arrStr.concat(arrNum);	lst_str.extend(lst_num)
var arrStr2 = arrStr.slice();	lst_str2 = lst_str.copy()

Tuple in Typescript vs Tuple in Python

Javascript	Python
var point = [“x”, “y”];	point = (“x”, “y”)
point[1];	point[1]
var arrTuple = [[“x”, “y”], [“w”, “z”]];	list_tuple = [(“x”, “y”), (“w”, “z”)]

function vs def

Javascript	Python
function greetMe(name){ console.log( "Hi! " + name ); }	def greet_me(name): print("Hi! " + name)
function greetMe(name){ return "Hi! " + name; }	def greet_me(name): return "Hi! " + name

If Statements

Javascript	Python
if ((1&&1)||(2 === 2)) { console.log("124"); } else if (1 !== 2) { console.log("421"); } else { console.log("Lakhan!"); }	if (1 and 1) or (2 == 2): print("124") elif (1 != 2): print("421") else: print("Lakhan!")

Objects vs Dictionaries

Javascript	Python
var objRomans = { "five": "V", "ten":"X" }	dict_romans = { "five": "V", "ten":"X" }
// Returns undefined // if key not exists objRomans["five"]	# throws an error # if key not exists dict_romans["five"]

Loops

Javascript	Python
var i = 0; var crossedLimit = false; while (i !== 10) { i += 1; crossedLimit = i==10; if (!crossedLimit) { console.log(i); } }	i = 0 crossed_limit=False while i != 10: i += 1 crossed_limit = i == 10 if not(crossed_limit): print(i)
var name = "Amit"; var l = name.length; for (var i = 0;i<l;i++) { console.log( name.charAt(i) ); }	name = "Amit" for char in name: print(char)
var names = ["A", "M"]; for (let name in names) { console.log( names[name] ); }	names = ["A", "M"] for name in names: print(name)

Comments

Javascript	Python
// single line comment	# single line comment
/* multi-line comment can be very long */	""" multi-line comment can be very long """

Imports

Javascript	Python
// imports everything // from cookies.js import "./cookies"; // imports `a` // from cookies.js import a from "./cookies";	# imports everything # from cookies.py import cookies # imports `a` # from cookies.py from cookies import a

Try Catch vs Try Except

Javascript	Python
try { let obj = JSON.parse("") } catch(e) { console.log(e.message); }	import json try: dict = json.loads("") except Exception as e: print(str(e))

Classes

Javascript	Python
class Bike { isBikeToo() { return true; } } class Car extends Bike { constructor( tire ) { super(); this.tire=tire; } whoAmI() { if(this.tire==3){ return "Auto"; } else { return "Bike"; } } } var c=new Car(3); console.log( c.tire, c.whoAmI(), c.isBikeToo() );	class Bike: def is_bike_too(self): return True class Car(Bike): def __init__(self, tire): self.tire = tire def who_am_i(self): if self.tire == 3: return "Auto" else: return "Bike" c = Car(3) print("{0} {1} {2}".format( str(c.tire), c.who_am_i(), str(c.is_bike_too()) ))

If you found this article useful in anyway, feel free to donate me and receive my dilettante painting as a token of appreciation for your donation.

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