Python基本语法总结大全(含java、js对比)

a = 10
b = "Hello"
c = True

if (x > 1) {
  console.log('ok')
}

if x > 1:
    print("ok")

age = 28               # int
price = 3.14           # float
name = "Tom"           # str
is_ok = True           # bool
arr = [1, 2, 3]        # list
t = (1, 2)             # tuple
user = {"name": "Tom"} # dict

if score > 90:
    print("A")
elif score > 60:
    print("B")
else:
    print("C")

for item in [1, 2, 3]:
    print(item)

for i in range(5):   # 0,1,2,3,4
    print(i)

for i in range(1, 5):  # 1,2,3,4
    print(i)

function add(a, b) {
  return a + b
}

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

def add(a, b) -> str:
    return a + b

class User {
  String name;
  User(String name) { this.name = name; }
}

class User:
    def __init__(self, name):
        self.name = name

u = User("Tom")
print(u.name)

name = "Tom"
age = 18
print(f"My name is {name}, age {age}")

arr = [1, 2, 3]

arr.append(4)
arr.insert(0, 100)
arr.remove(2)
print(len(arr))

squares = [x*x for x in range(5)]
print(squares)  # [0,1,4,9,16]

user = {
    "name": "Tom",
    "age": 20
}

print(user["name"])
user["age"] = 30

for key, val in user.items():
    print(key, val)

try:
    x = 10 / 0
except ZeroDivisionError:
    print("不能除以 0")
finally:
    print("done")

with open("test.txt", "r") as f:
    content = f.read()

with open("a.txt", "w") as f:
    f.write("hello")

import java.util.List;

import fs from 'fs';

import math
from math import sqrt

print(user)

python -m venv venv
source venv/bin/activate  # Mac/Linux
venv\Scripts\activate     # Windows

pip install requests

import requests

res = requests.get("https://api.github.com")
print(res.json())

a, b = 1, 2

msg = "ok" if x > 1 else "fail"

for index, item in enumerate(arr):
    print(index, item)

a, b = b, a

data = open("a.txt").read()

const arr = [];
for(let i=0; i<5; i++){
  arr.push(i * i);
}

squares = [x * x for x in range(5)]

evens = [x for x in range(10) if x % 2 == 0]

user = {"name": "Tom", "age": 18}

print(user["name"])
print(user.get("age"))

user["age"] = 20

for key, value in user.items():
    print(key, value)

try:
    1 / 0
except ZeroDivisionError as e:
    print("Error:", e)
finally:
    print("done")

with open("a.txt", "w", encoding="utf-8") as f:
    f.write("hello")

with open("a.txt", "r", encoding="utf-8") as f:
    content = f.read()

import math
print(math.sqrt(16))

from math import sqrt
print(sqrt(16))

import numpy as np

a, b = 1, 2

a, b = b, a

x, y, z = [10, 20, 30]

const add = (a, b) => a + b

add = lambda a, b: a + b

arr.sort(key=lambda x: x["age"])

def log(fn):
    def wrapper(*args, **kwargs):
        print("call", fn.__name__)
        return fn(*args, **kwargs)
    return wrapper

@log
def hello():
    print("hi")

pip install requests

pip install -U requests

python -m venv venv

source venv/bin/activate

venv\Scripts\activate

deactivate

import asyncio

async def hello():
    print("Hello")
    await asyncio.sleep(1)
    print("World")

asyncio.run(hello())

return f"It's always sunny in {city}!"

return `It's always sunny in ${city}!`

def get_weather(city: str) -> str:
    """Get weather for a given city."""
    return f"It's always sunny in {city}!"

/**
 * Get weather for a given city.
 */

def add(a: int, b: int) -> int:
    return a + b

print(add("hello", "world"))