我如何使python在文件的第一行之后随机选择一行？

Question

Is it possible to make python to randomly choose a line EXCEPT the first line of the file which is reserved for something else? Any help appreciated :)

with open(filename + '.txt') as f:        
    lines = f.readlines()         
    answer = random.choice(lines) 
    print(answer)

Answer 1

切片数组：

answer = random.choice(lines[1:])

Answer 2

You may also reserve the 1st line beforehand and freely use random selection:

with open(filename + '.txt') as f:
    reserved_line = next(f)   # reserved for something else
    lines = f.readlines()
    answer = random.choice(lines)

Answer 3

f.readlines() doesn't read every line from a file; it reads the remaining lines starting with the current file position.

with open(filename + '.txt') as f:        
    f.readline()  # read but discard the first line     
    lines = f.readlines()  # read the rest
    answer = random.choice(lines) 
    print(answer)

Since a file is its own iterator, though, there is no need to call readline or readlines directly. You can instead simply pass the file to list , using itertools.islice to skip the first line.

from itertools import islice

with open(filename + '.txt') as f:
    lines = list(islice(f, 1, None))
    answer = random.choice(lines)