函数与几项简单的模块
作者：互联网
检测指针当前位置
with open('a.txt','wt',encoding='utf-8') as f:
print(f.tell) # 检测指针当前位置所在
编写日志功能
import time # 使用 时间模块包
with open('日志的位置',mode='at',encoding='utf-8') as f:
f.write('%s ...内容\n' % time.strftime('%Y-%m-%d %H:%M:%S')) 后面时间格式
# 监控日志
with open('日志位置',mode='rb') as f:
f.seek(0,2) # 指针移动到末尾
while True:
line = f.realine()
if len(line) == 0:
continue
else:
print(line.decode('utf-8'), end='' )
修改文件的两种方式
1.
with open('a.txt',mode='rt',encoding='utf-8') as f:
res = f.read()
with open('a.txt',mode='wt',encoding='utf-8') as f:
f.write(res.replace('需要替换的内容...'，'替换成什么内容...'))
2.
import os
with open('a.txt',mode='rt',encoding='utf-8') as f,\
open('临时文件名...'，'wt',encoding='utf-8') as f1:
for line in f:
f1.write(line.replace('需要替换的内容...','替换成什么内容...'))
os.remove('a.txt')
os.rename('临时文件名...','a.txt')
函数
1.定义函数与调用函数
def func(): # func = 函数的内存地址
print('....')
func()
2.函数定义阶段发生的事情
申请内存空间，把函数体代码放进去，然后把内存地址绑定给函数名
def func():
print(1)
print(2)
3.函数调用阶段发生的事情：执行函数体代码
def func():
print(1)
print(2)
saadad
func()
# 函数定义阶段只检测语法不执行代码，只有在调用函数时才会执行函数体代码
例1
def bar():
print('from bar')
def foo():
print('from foo')
bar()
# from foo
foo() # from bar
例2
def foo():
print('from foo')
bar()
def bar():
print('from bar')
# from foo
foo() # from bar
4.函数的参数
例
def add(x,y):
res = x + y
print(res)
add(2,3)
def func(x,y):
if x > y:
print(x)
else:
print(y)
func(3333,4444)
def log(user,pwd):
if user == 'wuc' and pwd == '123'
print('ok')
else:
print('error')
log('wuc','123')
5.函数的返回值 return
函数内可以有多个return,但只要执行一次,整个函数就立即结束,并且将return后的值当作本次调用的产品返回
def max(sal1,sal2):
if sal1 > sal2:
return sal1
else:
return sal2
res = max(1000,2000)
print(res * 12)
#具体来说函数的返回值有三种形式
# 1 return 值: 返回的就是该值本身/-
# 2 return 值1,值2,值3:返回的是小元组
def func():
return 111,'aaa',[11,22]
x,y,z = func()
print(x,y,z)
# 没有return或者return无值或者return None:返回的都是None
del func():
res = 1+2
return
res = func()
print(res) # None
模块
"""
1 什么是模块
模块一系列功能的集合体
模块分为四种通用的类别
1 使用python编写的.py文件
2 已被编译为共享库或DLL的C或C++扩展
3 把一系列模块组织到一起的文件夹（注：文件夹下有一个__init__.py文件，该文件夹称之为包）
4 使用C编写并链接到python解释器的内置模块
模块有三种来源:
1 python自带的模块/库
内置模块
标准库
2 第三方的库
3 自定义库
2 为何要用模块
1 拿来主义,提升开发效率
2 减少代码冗余
3 如何用模块
import
from ... import
"""
例
import spam
print(spam.x)
print(spam.f1)
print(spam.f2)
def f1():
print('xxxxx')
spam.f1()
spam.f2()
from spam import x ,f1,f2
def f1():
print('xxxxx')
f1()
常用模块
时间戳
1. import time
print(time.time()) 1970到现在的秒数
2.格式化字符
print(time.strftime('%Y-%m-%d %H:%M:%S'))
3.结构化时间
obj = time.localtime()
print(obj.tm_year)
print(obj.tm_yday)
print(obj)
obj2 = time.gmtime() # utc时间
print(obj2)
random模块
# print(random.random())
# print(random.randint(1,3))
# print(random.randrange(1,3))
# print(random.choice([11,"aaa",333]))
# print(random.sample([11,"aaa",333,444],2))
# print(random.uniform(1, 3))
# item=[1,3,5,7,9]
# random.shuffle(item)
# print(item)
# 储备知识
# print(chr(65))
# print(chr(90))
#
# print(ord('A'))
# print(ord('Z'))
import random
# 随机验证码的命令
def make_code(size):
res = ''
for i in range(size):
num = str(random.randint(0,9))
s = chr(random.randint(65,90))
res += random.choice([num,s])
return res
print(make_code(6))
os 模块
import os
# print(os.getcwd()) # pwd
# os.makedirs('a/b/c/d')
# os.rmdir('a/b/c/d')
# os.removedirs('a/b/c/d')
# l = os.listdir(r'D:\py18期\day11')
# print(l)
# print(os.listdir('.'))
# print(os.listdir('..'))
# print(os.listdir('../..'))
# print(os.listdir('.'))
# print(os.listdir('..'))
# print(os.listdir('../..'))
# obj=os.stat('a.txt') # stat a.txt
# print(obj.st_size)
# print(os.sep)
# print(os.linesep)
# print(os.name)
# print(os.environ)
# os.environ['username'] = "egon"
#
# print(os.environ)
# print(os.path.abspath(r"a\b\c"))
# print(__file__)
# print(os.path.split(r"D:\a\b\c\d.txt"))
# print(os.path.dirname(os.path.dirname(r"D:\a\b\c\d.txt")))
# print(os.path.basename(r"D:\a\b\c\d.txt"))
# print(os.path.exists(r"D:\py18期\day11\代码\a"))
# print(os.path.exists(r"D:\py18期\day11\代码\a.txt"))
# print(os.path.isfile(r"D:\py18期\day11\代码\a"))
# print(os.path.isfile(r"D:\py18期\day11\代码\a.txt"))
# print(os.path.isdir(r"D:\py18期\day11\代码\a"))
# print(os.path.isdir(r"D:\py18期\day11\代码\a.txt"))
# print(os.path.isabs(r'D:\py18期\day11\代码\a'))
# print(os.path.getsize('a.txt'))
# print(os.path.join('D:\\', "a", 'b', 'c.txt'))
# print(os.path.join('D:\\', "a", "C:\\" 'b', 'c.txt'))
# print(os.path.dirname(os.path.dirname(__file__)))
# res = os.path.normpath(os.path.join(__file__,"..",'..'))
# print(res)
subprocess 模块
import os
# tasklist | findstr python.exe
# taskkill /F /PID 30060
# os.system('tasklist | findstr chrome')
# res = os.system('tasklist')
# print('='*50)
# print(res)
import subprocess
import time
obj = subprocess.Popen('tasklist',shell=True,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE
)
# print('hello')
# time.sleep(3)
res1 = obj.stdout.read()
res2 = obj.stderr.read()
print(res1.decode('gbk'))
print(res2)
标签：txt,函数,res,模块,print,path,几项,os,def 来源： https://www.cnblogs.com/wu-min/p/14876198.html