如何在python中拆分文件？

Question

是否可以拆分文件？例如,你有一个巨大的wordlist,我想拆分它,使它成为多个文件.这怎么可能？

Answer 1

这个文件按换行分割文件并将其写回.您可以轻松更改分隔符.如果您的输入文件中没有多个splitLen行(本例中为20),这也可以处理不均匀的数量.

splitLen = 20         # 20 lines per file
outputBase = 'output' # output.1.txt, output.2.txt, etc.

# This is shorthand and not friendly with memory
# on very large files (Sean Cavanagh), but it works.
input = open('input.txt', 'r').read().split('\n')

at = 1
for lines in range(0, len(input), splitLen):
    # First, get the list slice
    outputData = input[lines:lines+splitLen]

    # Now open the output file, join the new slice with newlines
    # and write it out. Then close the file.
    output = open(outputBase + str(at) + '.txt', 'w')
    output.write('\n'.join(outputData))
    output.close()

    # Increment the counter
    at += 1

Answer 2

sli的一个更好的循环示例,而不是占用内存:

splitLen = 20         # 20 lines per file
outputBase = 'output' # output.1.txt, output.2.txt, etc.

input = open('input.txt', 'r')

count = 0
at = 0
dest = None
for line in input:
    if count % splitLen == 0:
        if dest: dest.close()
        dest = open(outputBase + str(at) + '.txt', 'w')
        at += 1
    dest.write(line)
    count += 1

Answer 3

将二进制文件拆分为.000,.001等章节的解决方案:

FILE = 'scons-conversion.7z'

MAX  = 500*1024*1024  # 500Mb  - max chapter size
BUF  = 50*1024*1024*1024  # 50GB   - memory buffer size

chapters = 0
uglybuf  = ''
with open(FILE, 'rb') as src:
  while True:
    tgt = open(FILE + '.%03d' % chapters, 'wb')
    written = 0
    while written < MAX:
      if len(uglybuf) > 0:
        tgt.write(uglybuf)
      tgt.write(src.read(min(BUF, MAX - written)))
      written += min(BUF, MAX - written)
      uglybuf = src.read(1)
      if len(uglybuf) == 0:
        break
    tgt.close()
    if len(uglybuf) == 0:
      break
    chapters += 1

Answer 4

当然有可能：

open input file
open output file 1
count = 0
for each line in file:
    write to output file
    count = count + 1
    if count > maxlines:
         close output file
         open next output file
         count = 0