Question

我需要在文本文件的特定行中的单词后面添加字符串。原始文件是：

line 1: value1
line 2: value2
line 3: value3
line 4: value4
line 5: value5

例如，我想添加＆＃34; NAME＆＃34;在＆＃34; line＆＃34;之后的第3行所以文件将成为：

line 1: value1
line 2: value2
line NAME 3: value3
line 4: value4
line 5: value5

你会怎么做？

Answer 1

这将查找以“第3行：”开头的行，并仅编辑此行，保留其余部分，并将文本写入新文件。

with open('f1.txt', 'r') as f:
    lines = []
    for line in f:
        if line.startswith("line 3:"):
            split_line = line.split()
            split_line.insert(split_line.index("3:"), "NAME")
            lines.append(' '.join(split_line) + '\n')
        else:
            lines.append(line)

with open('f2.txt', 'w') as f:
    for line in lines:
        f.write(line)

当您运行以下代码时，

with open('f2.txt', 'r') as f:
    for line in f:
        print(line, end='')

打印：

line 1: value1
line 2: value2
line NAME 3: value3
line 4: value4
line 5: value5

Answer 2

with open(file, 'r') as f:
    lines = []
    for line in f:
        split_lines = line.split(':')
        if split_lines[0].endswith('3') is True:
            lines.append(split_lines[0][:-1] + NAME + split_lines[1:])
        else:
            lines.append(line)

Answer 3

我会考虑这个：

line_number = 3#I understood you know this. right ?
string_to_add = "NAME"#I understood you know this. right ?
string_to_find = "line"#I understood you know this. right ?
filename = "toto"
with open(filename,"r") as f:
    s = f.readlines()
s[line_number] = s[line_number].replace(string_to_find,string_to_find+string_to_add)
with open(filename,"w") as f:
    for line in s:
        f.write(line)

这似乎非常低效（对于大文件可能不太现实）。我很想看到更好的方法。

Python - 在文件的特定行中的单词后面添加字符串

3 个答案: