Question

新程序员在这里。因此，在我下面的代码中，“year1”集合就像它应该的那样工作并且向我吐出一些年份。虽然当我尝试为“year2”设置同样的东西时，它向我吐出的唯一东西是“set（）”。

我想知道这样做的代码是怎么回事？感谢您提前提供任何帮助！

def compare(word1, word2, startDate, endDate):
    with open('all_words.csv') as allWords:
        readWords = csv.reader(allWords, delimiter=',')
        year1 = set()
        for row in readWords:
            if int(startDate) <= int(row[1]) < int(endDate):
                if row[0] == word1:
                    year1.add(row[1])
        year2 = set()
        for row in readWords:
            if int(startDate) <= int(row[1]) < int(endDate):
                if row[0] == word2:
                    year2.add(row[1])

Answer 1

此时，您创建year2您已经阅读了整个文件（您已经在它的末尾）。所以你应该seek()到文件的开头再次通过它。所以：

....
allWords.seek(0)
year2 = set()
....

Answer 2

如上所述，如果没有重置，则无法迭代文件两次。您的流程中有重复的代码 - 您可以将重复分解出来并只迭代一次。

def compare(word1, word2, startDate, endDate):
    with open('all_words.csv') as allWords:
        readWords = csv.reader(allWords, delimiter=',')
        year1 = set()
        year2 = set()
        for row in readWords:
            if int(startDate) <= int(row[1]) < int(endDate):
                if row[0] == word1:
                    year1.add(row[1])
                if row[0] == word2:
                    year2.add(row[1])

不确定为什么我的代码吐出一个空集

2 个答案: