变量 用下划线分割,而不是驼峰,因为下划线更清晰,如含有A的变量,ACar -> a_car
input() 用户输入 不过输入的是字符串:
user_input = input('Hey user, enter a number')
字符串函数可以进行字符串相关的判断:
isidentifier() 判断字符串是否为有效的python字符串
'hello'.isidentifier() // True
'3_hello'.isidentifier() // True
isdigit() 判断是否是正整数(正常的计数单位):
print('10'.isdigit()) // True
print('0'.isdigit()) // True
print('1.5'.isdigit()) // False
print('-5'.isdigit()) // False
定义函数,全靠冒号、缩进表示:
def days_to_units(num_of_days):
if num_of_days > 0:
return '!!!'
调用函数:
days_to_units(3)
条件判断和嵌套:
if user_input_number.isdigit():
if user_input_number > 0:
print('!!!')
elif user_input_number === 0:
print('000')
else:
print('@@@')
错误捕捉try except:
try:
user_input = input('Hey user, enter a number')
user_input_number = int(user_input)
except ValueError: # 这里也可以不写具体错误类型
print("your input is not a valid number.")
while循环:
user_input = ""
while user_input != "exit":
user_input = input("please enter")
print(user_input)
字符串split转list类型:
user_input = input('Hey user, enter a number')
for num_of_days_element in user_input.split(","):
print(num_of_days_element)
注释:
# 单行
"""
我是多行注释
我是多行注释
"""
set类型 获取到唯一的元素列表:
print(set([1,1,2,3,4,5]))
print({1,1,2,3,4,5})
type类型 获取元素的类型:
type(set([1,1,2,3,4,5])) # <class 'set'>
dict类型:
print(type([1, 2, 3])) # <class 'list'>
print(type(['1', '2', '3'])) # <class 'list'>
float类型
print(type(1.2)) # <class 'float'>
bool类型
print(type(True)) # <class 'bool'>
int类型
print(type(1)) # <class 'int'>
float类型
print(type(1.2)) # <class 'float'>
py文件中引入其他py文件(引入某些函数)
main.py:
from helper import print_asd # from helper import * 全部引入
print_asd()
helper.py:
print('ss')
def print_asd():
print('asd')
py文件引入其他py文件(全部引入)
main.py:
import helper
helper.print_asd()
helper.py:
print('ss')
def print_asd():
print('asd')
引入别名(模块整体):
import helper as h
print(h.user_input_message)
引入别名(方法、变量):
from helper import user_input_message as uim
print(uim)
内置函数:
import math
print(math.pow(2, 4)) # 16.0
from datetime import datetime, timezone
now = datetime.now()
print(datetime(2022, 6, 9, 12, 27, 25)) # 2022-06-09 12:27:25
print(timezone.utc) # UTC
import os
print(os.name) # nt
import logging
logger = logging.getLogger('MAIN')
logger.error('Error happened in the app') # Error happened in the app
import datetime
print(datetime.datetime.strptime("12.07.2021", "%d.%m.%Y")) #2021-07-12 00:00:00
print(type(datetime.datetime.strptime("12.07.2021", "%d.%m.%Y"))) #<class 'datetime.datetime'>
计算平均数 内置函数 处理list非常方便:
numlist = list()
while (True):
inp = input('Enter a number: ')
if inp == 'done': break
value = float(inp)
numlist.append(value)
average = sum(numlist) / len(numlist)
print('Average:', average)
写入文件:
fhand = open('a.txt','w')
fhand.write('zsf')
fhand.close()
定义类(删除钩子):
class PartyAnimal:
x = 0
def __init__(self):
print('I am constructed')
def party(self) :
self.x = self.x + 1
print('So far',self.x)
def __del__(self):
print('I am destructed', self.x)
an = PartyAnimal()
an.party()
an.party()
an = 42
print('an contains',an)
---
pc里ctrl+shift+F10 运行
包管理器 https://pypi.org
https://www.bilibili.com/video/BV1XY411p7Cx
官方文档:https://docs.python.org/3.10/library/stdtypes.html#str.isdecimal
打包exe工具:Nuitka