Python根据URL地址下载文件并保存至对应目录的实现

引言

在编程中经常会遇到图片等数据集将图片等数据以URL形式存储在txt文档中，为便于后续的分析，需要将其下载下来，并按照文件夹分类存储。本文以Github中Alexander Kim提供的图片分类数据集为例，下载其提供的图片样本并分类保存

Python 3.6.5，Anaconda， VSCode

1. 下载数据集文件

建立项目文件夹，下载上述Github项目中的raw_data文件夹，并保存至项目目录中。

2. 获取样本文件位置

编写get_doc_path.py，根据根目录位置，获取目录及其子目录所有数据集文件

import os def get_file(root_path, all_files={}): 递归函数，遍历该文档目录和子目录下的所有文件，获取其path files = os.listdir(root_path) for file in files: if not os.path.isdir(root_path + / + file): # not a dir all_files[file] = root_path + / + file else: # is a dir get_file((root_path+/+file), all_files) return all_files if __name__ == __main__: path = ./raw_data print(get_file(path))

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3. 下载文件

3.1 读取url列表并

for filename, path in paths.items(): print(reading file: {}.format(filename)) with open(path, r) as f: lines = f.readlines() url_list = [] for line in lines: url_list.append(line.strip(n)) print(url_list)

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3.2 创建文件夹

foldername = “./picture_get_by_url/pic_download/{}”.format(filename.split(.)[0]) if not os.path.exists(folder_path): print(“Selected folder not exist, try to create it.”) os.makedirs(folder_path)

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3.3 下载图片

def get_pic_by_url(folder_path, lists): if not os.path.exists(folder_path): print(“Selected folder not exist, try to create it.”) os.makedirs(folder_path) for url in lists: print(“Try downloading file: {}”.format(url)) filename = url.split(/)[–1] filepath = folder_path + / + filename if os.path.exists(filepath): print(“File have already exist. skip”) else: try: urllib.request.urlretrieve(url, filename=filepath) except Exception as e: print(“Error occurred when downloading file, error message:”) print(e)

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4. 完整源码

4.1 get_doc_path.py

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4.2 get_pic.py

import get_doc_path import os import urllib.request def get_pic_by_url(folder_path, lists): if not os.path.exists(folder_path): print(“Selected folder not exist, try to create it.”) os.makedirs(folder_path) for url in lists: print(“Try downloading file: {}”.format(url)) filename = url.split(/)[–1] filepath = folder_path + / + filename if os.path.exists(filepath): print(“File have already exist. skip”) else: try: urllib.request.urlretrieve(url, filename=filepath) except Exception as e: print(“Error occurred when downloading file, error message:”) print(e) if __name__ == “__main__”: root_path = ./picture_get_by_url/raw_data paths = get_doc_path.get_file(root_path) print(paths) for filename, path in paths.items(): print(reading file: {}.format(filename)) with open(path, r) as f: lines = f.readlines() url_list = [] for line in lines: url_list.append(line.strip(n)) foldername = “./picture_get_by_url/pic_download/{}”.format(filename.split(.)[0]) get_pic_by_url(foldername, url_list)

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4.3 运行结果

执行get_pic.py

当程序意外停止或再次执行时，程序会自动跳过文件夹中已下载的文件，继续下载未下载的内容

{‘urls_drawings.txt: ‘./picture_get_by_url/raw_data/drawings/urls_drawings.txt, ‘urls_hentai.txt: ‘./picture_get_by_url/raw_data/hentai/urls_hentai.txt, ‘urls_neutral.txt: ‘./picture_get_by_url/raw_data/neutral/urls_neutral.txt, ‘urls_porn.txt: ‘./picture_get_by_url/raw_data/porn/urls_porn.txt, ‘urls_sexy.txt: ‘./picture_get_by_url/raw_data/sexy/urls_sexy.txt}

reading file: urls_drawings.txt

Try downloading file: http://41.media.tumblr.com/xxxxxx.jpg

Try downloading file: http://ak1.polyvoreimg.com/cgi/img-thing/size/l/tid/xxxxxx.jpg

Error occurred when downloading file, error message:

HTTP Error 502: No data received from server or forwarder

Try downloading file: http://akicocotte.weblike.jp/gaugau/xxxxxx.jpg

Try downloading file: http://animewriter.files.wordpress.com/2009/01/nagisa-xxxxxx-xxxxxx.jpg

Try downloading file: http://cdn.awwni.me/xxxxxx.jpg