The difference between readline and readlines in python

1.readline scenario

f0=file("readline.txt",r)
while true
    for line in f0.readline()
if not line: break
pass #do something

The usage of readline is about 3 times faster than fileinput, 30,000-40,000 lines per second. The advantage is that it can be read line by line and does not occupy memory. It is suitable for processing larger files, such as Files that exceed the memory size

2.readlines scenario

f1=open("readline.txt","r")
for line in f1.readlines()#跟上面的方式不同
print line

readlines will read all the files into the memory, greatly increasing the speed, but if you don’t have such a large memory, you can only use readline