尝试向文本文件中模式的所有实例添加递增数字

Question

我是一个完整的初学者，从今天开始，但几年前我做了一点 C++，我正在尝试编写一个代码来读取文本文件并在每个递增模式的开头添加一个数字进一步阅读。

到目前为止，我已经写了：

import tkinter as tk
import re

master = tk.Tk()
from tkinter.filedialog import askopenfilename

filename = askopenfilename()
file = open(filename, "r+")
filetext = file.read()
pattern = '"name":"(.*?)"'
name = re.findall(pattern, filetext)
print (name)
namereplace = re.sub(pattern, "test", filetext)
print ("this ran")
file.close()

这会打开选择文本文件的提示，读取文本文件并找到我需要添加订单的所有字符串，但不会将它们替换为"test"。

Answer 1

首先，要在文件中进行替换，您需要将结果实际写回文件。

为此，您有两个选择 (cmp.Replace and overwrite instead of appending)：

1. 只需在读取文件后以w 模式再次打开文件并将替换的输出写入其中即可：

import tkinter as tk
import re

master = tk.Tk()
from tkinter.filedialog import askopenfilename

filename = askopenfilename()
pattern = '"name":"(.*?)"'

with open(filename, "r") as infile:
    filetext = infile.read()
    infile.close()

with open(filename, "w") as outfile:
    outfile.write(re.sub(pattern, "test", filetext))
    outfile.close()

1. 使用seek 移动文件的开头并使用truncate 就地替换：

import tkinter as tk
import re

master = tk.Tk()
from tkinter.filedialog import askopenfilename

filename = askopenfilename()
pattern = '"name":"(.*?)"'

with open(filename, "r+") as infile:
    filetext = infile.read()
    infile.seek(0)
    infile.write(re.sub(pattern, "test", filetext))
    infile.truncate()
    infile.close()

其次，关于你问题的主要部分，用递增的数字替换：我认为你不能通过一次调用 re.sub() 来做到这一点。

您可以做的是逐行读取文件并逐行替换计数器变量。每当您成功匹配时，您都会在之后增加您的计数器。要确定这一点，您可以例如使用re.subn()，它不仅会返回新字符串，还会返回替换的次数。

完整示例：

import tkinter as tk
import re

master = tk.Tk()
from tkinter.filedialog import askopenfilename

filename = askopenfilename()
pattern = '"name":"(.*?)"'

with open(filename, "r") as infile:
    filetext = ""
    count = 1
    line = infile.readline()
    while line:
        matchtuple = re.subn(pattern, str(count), line)
        if matchtuple[1]:
            count += 1
        filetext += matchtuple[0]
        line = infile.readline()
    infile.close()

with open(filename, "w") as outfile:
    outfile.write(filetext)
    outfile.close()

输入：

"bla":"bal"
"name":"baba"
"blah":"blah"
"name":"keke"

输出：

"bla":"bal"
1
"blah":"blah"
2