Question

我的文本文件如下：

first line  
second line  
third line  
forth line  
fifth line  
sixth line

我想用三个新行替换第三行和第四行。以上内容将成为：

first line  
second line  
new line1  
new line2  
new line3    
fifth line  
sixth line

如何使用Python执行此操作？

Answer 1

python2.6

with open("file1") as infile:
    with open("file2","w") as outfile:
        for i,line in enumerate(infile):
            if i==2:
                # 3rd line
                outfile.write("new line1\n")
                outfile.write("new line2\n")
                outfile.write("new line3\n")
            elif i==3:
                # 4th line
                pass
            else:
                outfile.write(line)

python3.1

with open("file1") as infile, open("file2","w") as outfile:
    for i,line in enumerate(infile):
        if i==2:
            # 3rd line
            outfile.write("new line1\n")
            outfile.write("new line2\n")
            outfile.write("new line3\n")
        elif i==3:
            # 4th line
            pass
        else:
            outfile.write(line)

Answer 2

import fileinput
myinsert="""new line1\nnew line2\nnew line3"""
for line in fileinput.input("file",inplace=1):
    linenum=fileinput.lineno()
    if linenum==1 or linenum>4 : 
        line=line.rstrip()
    if linenum==2:
        line=line+myinsert
    print line

或者如果你的文件不是太大，

import os
myinsert=["new line3\n","new line2\n","new line1\n"]
data=open("file").readlines()
data[2:4]=""
for i in myinsert:data.insert(2,i)
open("outfile","w").write(''.join(data))
os.rename("outfile","file)

Answer 3

将整个文件作为行列表读取，然后用新的行列表替换要删除的行：

f = open('file.txt')
data = f.readlines()
f.close()
data[2:4] = [
    'new line1\n',
    'new line2\n',
    'new line3\n']
f = open('processed.txt','w')
f.writelines(data)
f.close()

请注意，列表切片是从零开始的，[2：4]表示“元素2最多但不包括元素4”。

Answer 4

打开第二个文件，写入，读取然后写下要复制的行，写新行，读取要跳过的行，然后复制其余行。

Answer 5

import os
i = open(inputFilePath, 'r')
o = open(inputFilePath+"New", 'w')

lineNo = 0
for line in input:
    lineNo += 1
    if lineNo != 3:
        o.write(line)
    else:
        o.write(myNewLines)

i.close()
o.close()
os.remove(inputFilePath)
os.rename(inputFilePath+"New", inputFilePath)

希望这有帮助

Answer 6

有几种方法可以实现这个目标

如果您的文件很小并且您的行是唯一的，您可以只读取整个文件并替换该行，例如

f.read（）。replace（“第三行”，“new line1 \ nnew line2 \ nnew line3”）
但是如果文件很大或行不是unqiue，只需逐行读取文件，并输出每一行但在第三行输出三行不同

e.g

for i, line in enumerate(f):
    if i == 2:
        o.write(myThreelines)
    else:
        o.write(line)

删除并在文本文件中插入行

6 个答案: