如何在Python中写入文件中的特定行？

如何在Python中写入文件中的特定行？

with open('input') as fin, open('output','w') as fout:    for line in fin:        fout.write(line)        if line == 'xxxxxn':next_line = next(fin)if next_line == 'yyyyyn':   fout.write('my_linen')fout.write(next_line)

这将插入之间的线路 每 发生

xxxxxn

并

yyyyyn

在文件中。

另一种方法是编写一个函数以产生行，直到看到一个

xxxxxnyyyyyn

 def getlines(fobj,line1,line2):     for line in iter(fobj.readline,''):  #This is necessary to get `fobj.tell` to work         yield line         if line == line1:  pos = fobj.tell()  next_line = next(fobj):  fobj.seek(pos)  if next_line == line2:      return

然后，您可以使用此方法直接传递给

writelines

：

with open('input') as fin, open('output','w') as fout:    fout.writelines(getlines(fin,'xxxxxn','yyyyyn'))    fout.write('my_linen')    fout.writelines(fin)