import os #导入

示例1

data = open('xingdong.txt') #打开文件并把内容赋予到data
print(data.readline(),end='')#读取第一行

print(data.readline(),end='')#继续往下读取，第二行
data.seek(0)#回归到文件开始位置

print(data.readline(),end='')

示例2

for each_line in data: #遍历文件内容

    if not each_line.find(':') == -1:  #find()如果字符串中没有：，则返回-1，not相反
        (name,speak) = each_line.split(':',1)#分隔，第一个
        print(name,end='')
        print(' said:',end='')
        print(speak,end='')

示例3

action=[]

xingdong=[]

for each_line in data:
    if not each_line.find(':') == -1:
        (name,speak) = each_line.split(':',1)
        speak = speak.strip()  #删除空白符
        if name=='action':
            action.append(speak)
        elif name=='xingdong':
            xingdong.append(speak)
        else:
        print('error')

示例4

with open('action.txt','w+') as action_data,open('xingdong.txt','w+') as xingdong_data: #不需要关闭close()
    for action_say in action:
        print(action_say,file=action_data)
    for xingdong_say in xingdong:
        print(xingdong_say,file=xingdong_data)

示例5

if os.path.exists(filename): #判断文件是否存在
    message = 'the file is  exists'
else:
    message = "the file is none"
print(message)

示例6

for root,dirs,files in os.walk('c:\\python'): #遍历文件夹
    for filespath in files:
        print(os.path.join(root,filespath))