JavaScript 就像 Python

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发布时间：2024-11-14 16:49:49

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来源于dev.to

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javascript 就像 python

本文对 javascript 和 python 的语法和基本编程结构进行了比较。它旨在强调这两种流行的编程语言在实现基本编程概念方面的相似之处。

虽然两种语言有许多共同点，使开发人员更容易在它们之间切换或理解对方的代码，但也应该注意明显的语法和操作差异。

重要的是要以轻松的角度进行这种比较，而不是过分强调 javascript 和 python 之间的相似或差异。目的不是要声明一种语言优于另一种语言，而是提供一种资源，可以帮助熟悉 python 的程序员更轻松地理解并过渡到 javascript。

你好世界

javascript

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// in codeguppy.com environment
println('hello, world');

// outside codeguppy.com
console.log('hello, world');

python

print('hello, world')

变量和常量

javascript

let myvariable = 100;

const myconstant = 3.14159;

python

myvariable = 100

myconstant = 3.14159

字符串插值

javascript

let a = 100;
let b = 200;

println(`sum of ${a} and ${b} is ${a + b}`);

python

a = 100
b = 200

print(f'sum of {a} and {b} is {a + b}')

if 表达式/语句

javascript

let age = 18;

if (age < 13) 
{
    println("child");
} 
else if (age < 20) 
{
    println("teenager");
} 
else 
{
    println("adult");
}

python

age = 18

if age < 13:
    print("child")
elif age < 20:
    print("teenager")
else:
    print("adult")

条件句

javascript

let age = 20;
let message = age >= 18 ? "can vote" : "cannot vote";
println(message);  // output: can vote

python

age = 20
message = "can vote" if age >= 18 else "cannot vote"
print(message)  # output: can vote

数组

javascript

// creating an array
let myarray = [1, 2, 3, 4, 5];

// accessing elements
println(myarray[0]);  // access the first element: 1
println(myarray[3]);  // access the fourth element: 4

// modifying an element
myarray[2] = 30;  // change the third element from 3 to 30

// adding a new element
myarray.push(6);  // add a new element to the end

python

# creating a list to represent an array
my_array = [1, 2, 3, 4, 5]

# accessing elements
print(my_array[0])  # access the first element: 1
print(my_array[3])  # access the fourth element: 4

# modifying an element
my_array[2] = 30  # change the third element from 3 to 30

# adding a new element
my_array.append(6)  # add a new element to the end

对于每个

javascript

let fruits = ["apple", "banana", "cherry", "date"];

for(let fruit of fruits)
    println(fruit);

python

fruits = ["apple", "banana", "cherry", "date"]

for fruit in fruits:
    print(fruit)

词典

javascript

// creating a dictionary
fruit_prices = {
    apple: 0.65,
    banana: 0.35,
    cherry: 0.85
};

// accessing a value by key
println(fruit_prices["apple"]);  // output: 0.65

python

# creating a dictionary
fruit_prices = {
    "apple": 0.65,
    "banana": 0.35,
    "cherry": 0.85
}

# accessing a value by key
print(fruit_prices["apple"])  # output: 0.65

功能

javascript

function addnumbers(a, b) 
{
    return a + b;
}

let result = addnumbers(100, 200);
println("the sum is: ", result);

python

def add_numbers(a, b):
    return a + b

result = add_numbers(100, 200)
print("the sum is: ", result)

元组返回

javascript

function getcircleproperties(radius) 
{
    const area = math.pi * radius ** 2;
    const circumference = 2 * math.pi * radius;

    return [area, circumference];  // return as an array
}

// using the function
const [area, circumference] = getcircleproperties(5);

println(`the area of the circle is: ${area}`);
println(`the circumference of the circle is: ${circumference}`);

python

import math

def getcircleproperties(radius):
    """calculate and return the area and circumference of a circle."""
    area = math.pi * radius**2
    circumference = 2 * math.pi * radius
    return (area, circumference)

# using the function
radius = 5
area, circumference = getcircleproperties(radius)

print(f"the area of the circle is: {area}")
print(f"the circumference of the circle is: {circumference}")

可变数量的参数

javascript

function sumnumbers(...args) 
{
    let sum = 0;
    for(let i of args)
        sum += i;
    return sum;
}

println(sumnumbers(1, 2, 3));
println(sumnumbers(100, 200));

python

def sum_numbers(*args):
    sum = 0
    for i in args:
        sum += i
    return sum

print(sum_numbers(1, 2, 3))
print(sum_numbers(100, 200))

拉姆达斯

javascript

const numbers = [1, 2, 3, 4, 5];

// use map to apply a function to all elements of the array
const squarednumbers = numbers.map(x => x ** 2);

println(squarednumbers);  // output: [1, 4, 9, 16, 25]

python

numbers = [1, 2, 3, 4, 5]

# use map to apply a function to all elements of the list
squared_numbers = map(lambda x: x**2, numbers)

# convert map object to a list to print the results
squared_numbers_list = list(squared_numbers)

print(squared_numbers_list)  # output: [1, 4, 9, 16, 25]

课程

javascript

class book 
{
    constructor(title, author, pages) 
    {
        this.title = title;
        this.author = author;
        this.pages = pages;
    }

    describebook() 
    {
        println(`book title: ${this.title}`);
        println(`author: ${this.author}`);
        println(`number of pages: ${this.pages}`);
    }
}

python

class book:
    def __init__(self, title, author, pages):
        self.title = title
        self.author = author
        self.pages = pages

    def describe_book(self):
        print(f"book title: {self.title}")
        print(f"author: {self.author}")
        print(f"number of pages: {self.pages}")

类的使用

javascript

// creating an instance of the book class
// this is actually a real book (see curriculum section for more info)
const mybook = new book("illustrated javascript", "adrian", 684);
mybook.describebook();

python

# Creating an instance of the Book class
# This is actually a real book (see Curriculum section for more info)
my_book = Book("Illustrated JavaScript", "Adrian", 684)
my_book.describe_book()