特定行数的Loadtext [英] Loadtext for specific number of lines

问题描述

我要加载的文件很大，所以无法直接打开它.我想我必须分多个部分阅读它.

I have a huge file to load so I can't open it directly. I think I have to read it in multiple parts.

例如，为了使用第1到50行，我尝试了类似的方法，但是它不起作用:

For instance, in order to use lines 1 to 50, I tried with something like that, but it doesn't work:

import numpy as np

with open('test.txt') as f:
    lines = (line for line in f if line < 50.)
    FH = np.loadtxt(lines, delimiter=',', skiprows=1)

推荐答案

在Python 3中，请尝试以下操作:

In Python 3, please try this:

a = 0
f = open('test.txt')
while a < 50:
    a = a + 1
    print(f.readline(), end='')
else:
    f.close()

在Python 2中，使用此命令:

In Python 2, use this:

a = 0
f = open('test.txt')
while a < 50:
    a = a + 1
    print f.readline(),
else:
    f.close()

或选择这种方式，请使用readlines():

or choose this way, use readlines():

with open('test.txt') as f:
    text = f.readlines()

readlines()将创建一个列表，并且一行是一个对象.因此，如果您需要20到50行，可以执行以下操作:

readlines() will create a list, and one line is one object. so if you want the 20 - 50 lines, you can do this:

for i in text[20:50]:
    print(i)

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