python 文件读取的方法

1.、 read
f = open(‘test/gbk.txt’, ‘r+’, encoding=‘utf-8’)
print(f.read())
优点：将数据整体读取，放入一个字符串变量中
缺点：如果文件过大导致内存泄漏

2、readline
with open(fileName) as f:
dataLine = f.readline()
while dataLine:
print(dataLine)
dataLine = f.readline()
优点：每次读取一行
缺点：效率慢

3、readlines
自动将文件读取为一个列表, 按照每行划分
with open(fileName) as f:
data = f.readlines()
print(data)
优点：速度快
缺点：造成内存泄漏
4、生成器读取数据
def readfile(fileName):
with open(fileName) as f:
while True:
data = f.readline().strip()
if data is None or not data:
break
yiled data
for data in readfile():
print(data)

优点：读取不造成内存泄漏