python 两行读文件内容 python如何一行行读取文件

0. 读取文件

# 1
f = open('fileName', 'r')
# do something with f
f.close()

# 2
with open('fileName', 'r') as f:
    # do something with f
    # no need to close, and will close automatically if exception rised

1. 全部一口气读取，一个文件是一个list，每一个元素（str）是一行

lines = f.readlines()
for line in lines:
    fun(line)

2. 逐行读取

简易版：每次循环只能读取一行

for line in f:
    fun(f)

自由一点：每次可以视情况，读取多行(推荐，多写一行，获得更多的控制权)

line = f.readline()
while line:
    fun(line, f) # can read more line by f.readline()
    line = f.readline()