Python:给定两个文件名列表，根据日期部分查找常见文件名

Question

我有两个数据源，每个数据源都有一个文件列表。要求是比较两个列表并找出具有相同时间戳的文件，然后根据有关我想查看哪个源的输入参数输出结果列表。

一个复杂之处是我们无法进行直接的文件名比较，因为它们被有关源的字符串包裹，我们需要首先提取日期部分并仅进行比较，然后返回原始文件名。

如果没有大量 Python 工作知识，我觉得我所尝试的方法不够有效。例如，我能够从两个源中提取日期部分并将它们与一段代码进行比较，但随后不确定如何将它们恢复到原始文件名。

listA = ["apple://folderx/foldery/sourcea_20190326-0.json", "apple://folderx/foldery/sourcea_20190323-1.json", "apple://folderx/foldery/sourcea_20190324-1.json"]
listB = ["apple://folderx/folderz/source_b_20190324-0.json", "apple://folderx/folderz/source_b_20190326-0.json"]

mySource = ['A', 'B']
allDates = {}
for s in mySource:
    fileList = []
    dateList = []

    if s == 'A':
        fileList = listA
    elif s == 'B':
        fileList = listB
    for f in fileList:
        date = f.rsplit('_',1)[-1].split('-')[0]
        if not date in dateList:
            dateList.append(date)

        if len(dateList) > 0:
            allDates[s] = dateList

        else:
            time.sleep(10)        
    if len(fileList) == 0:
        raise NoDataException

list(set(allDates['A']).intersection(allDates['B']))

这段代码只是返回两个源文件之间的公共(public)日期列表。

输出为:

['20190326', '20190324'].

我正在寻找的是

listA = ["apple://folderx/foldery/sourcea_20190326-0.json", "apple://folderx/foldery/sourcea_20190324-1.json"] 
listB = ["apple://folderx/folderz/source_b_20190324-0.json", "apple://folderx/folderz/source_b_20190326-0.json"] 

Answer 1

您可以为 listA 和 listB 构建字典，将日期映射到文件名，使用集合交集获取公共(public)键(日期)，然后将日期映射回listA 和 listB 的文件名:

a, b = {}, {}
for l, d in (listA, a), (listB, b):
    for f in l:
        d.setdefault(f.rsplit('_', 1)[-1].split('-')[0], []).append(f)
common_keys = a.keys() & b.keys()
listA, listB = ([f for k in common_keys for f in d[k]] for d in (a, b))

因此给定:

listA = ["apple://folderx/foldery/sourcea_20190326-0.json", "apple://folderx/foldery/sourcea_20190323-1.json", "apple://folderx/foldery/sourcea_20190324-1.json"]
listB = ["apple://folderx/folderz/source_b_20190324-0.json", "apple://folderx/folderz/source_b_20190326-0.json", "apple://folderx/folderz/source_c_20190324-0.json"]

listA 变为:

['apple://folderx/foldery/sourcea_20190324-1.json', 'apple://folderx/foldery/sourcea_20190326-0.json']

listB 变为:

['apple://folderx/folderz/source_b_20190324-0.json', 'apple://folderx/folderz/source_c_20190324-0.json', 'apple://folderx/folderz/source_b_20190326-0.json']