Question

我在＆quot; origFile＆＃39;中有一个网址列表这将被扩充并写入＆ready;＆＃39; readyFile＆＃39;。我想将网址添加到readyFile＆＃39;只有当他们还没有出现在＆ready文件中时...

with open('bpBlacklist.txt', 'r') as origFile, open('bpBlacklistReady','r+') as readyFile :
    for line in origFile:       
        orig_string = line.strip()
        if orig_string in readyFile.read():
            None
        else: 
            readyFile.write( "'" + orig_string + "'," + '\n' )

    origFile.close()    
    readyFile.close()

现在，它只是将整个列表重写为＆ready;＆＃39; readyFile＆＃39;每次我运行它。我试着移动＆＃34;＆＃39; + str +＆＃39;＆＃34; if语句之外的扩充，但问题仍然存在。

Answer 1

通过撰写readyFile.write(...)，您的下一个readyFile.read()电话将被覆盖。您应该在with语句后立即将readyFile内容保存到变量中：

with open('bpBlacklist.txt', 'r') as origFile, open('bpBlacklistReady','r+') as readyFile :
     readyFileContent = readyFile.read()

Answer 2

您的情况无法正常工作，因为read()方法会将整个文件作为字符串返回。您需要检查可迭代网址之间的成员资格。

而不是循环遍历文件并检查所有网址的成员资格，您可以使用set.difference()函数找到差异，然后编写额外的网址：

with open('bpBlacklist.txt', 'r') as origFile, open('bpBlacklistReady','r+') as readyFile :
    current = set(origFile)
    diffs = current.difference(readyFile.readlines())
    for url in diffs:
        readyFile.write(url + '\n')

字符串比较无法识别匹配

2 个答案: