Can read() and readlines() work together when reading a file in Python?

Question

I'm a Python beginner, and I'm doing some tests of file operations. I just read a file with read() and readlines() . Each of them works perfectly, respectively. However, when I add a readlines() to read the appointed file after read() , I surprisingly find that I can't read anything from the file using readlines() .

PS I tried to switch the places of them, and the latter function can't read anything from the file yet.

So, how do the functions actually work?

Below is my code:

filea = open('/Users/gssflyaway/Documents/web/echarts-2.2.7/LICENSE.TXT')
print filea.readlines()
print '-' * 50
print filea.read()
filea.close()

the result by Pycharm

Answer 1

Files are read from the disk by moving a pointer (like a bookmark so that the file object knows where it left) around. A read operation advances the pointer and if you read the whole file, the pointer will be at the very end of the file. Same applies to both readlines and read . If you want to re-read the file, you can use seek to reset the pointer to the beginning to start a new round.

filea.seek(0)