将路径名写入文件 (Python)

Question

我正在处理大量图像并尝试搜索 jpeg，然后将它们的路径写入文件。

目前，我可以找到我想要的所有 jpeg。但是，我的“索引”文件中的每个新路径都会覆盖最后一个。因此，它根本不是一个索引/列表，而是一个包含 a/path/to/just/one/file.jpg 的文本文件

我已经简化了我的代码并在下面添加了它。这很冗长，但这是为了我的阅读利益以及像我这样的新人。

#----------
#-->Import Modules

#I'm pretty sure there is redundancy here and it's not well laid out
#but I'm new to coding and it works

import os
import pathlib

import glob, os
from pathlib import Path

import os.path
from os import path

#----------
#-->Global Vars

#Simplified example of my variables
working_dir = "/Users/myname/path/to/working dir"
records_dir = str(working_dir + "/Records")

#----------
#-->Search Location

#Define where the jpeg search is to take place
#(actually dictated via user input, Minecraft is just an example)
search_locations = ["/Users/myname/minecraft"]

#---------
#--> Search for jpgs and write their paths to a file

#define the file where the jpeg paths are to be stored,
#(I'm referring to the storage file as an index of sorts)
jpg_index = str(records_dir + "/index_for_all_jpgs")


#Its embedded in a forloop because the user can add multiple locations
for search_location in search_locations:
    #get the desired paths from the search location
    for path in Path(search_location).rglob('*.jpg'):
        #Open the index where paths are to be stored
        with open(jpg_index, 'w') as filehandle:
            #This is supposed to write each paths as a new line
            #But it doesn't work
            filehandle.writelines('%s\n' % path)

我也尝试过使用更简单的想法；

filehandle.write(path)

还有一个我不完全理解的更复杂的；

filehandle.writelines("%s\n" % path for path in search_location)

然而我所做的一切都以稍微不同的方式失败了。

Answer 1

'w' 选项告诉 open() 方法覆盖 jpg_index 文件中以前的任何内容。因为每次在写入 jpeg 路径之前都会调用此方法，所以只剩下最后一个。使用 'a' (append) 代替 'w' (write) 来告诉 open() 方法追加到文件而不是每次都覆盖它。

例如：

for search_location in search_locations:
    for path in Path(search_location).rglob('*.jpg'):
        with open(jpg_index, 'a') as filehandle:
            filehandle.writelines('%s\n' % path)

或者，您可以将 with... as 语句移到 for 循环之外。这样，jpg_index文件只会在开始时打开并覆盖一次，而不是在其中已有信息之后。

例如：

with open(jpg_index, 'w') as filehandle:
    for search_location in search_locations:
        for path in Path(search_location).rglob('*.jpg'):
            filehandle.writelines('%s\n' % path)