Question

我的目标是拥有一个列表列表，其中外部列表中的每个项目都包含第一个索引中的单词，以及它在第二个索引中遇到它的次数。例如，它应该如下所示：

[["test1",0],["test2",4],["test3",8]]

唯一的问题是，当我尝试从第一个内部列表中访问单词“test1”时，我得到一个索引超出范围错误。以下是我尝试执行此操作的代码：

stemmedList = [[]]

f = open(a_document_name, 'r')

#read each line of file
fileLines = f.readlines()
for fileLine in fileLines:
    #here we end up with stopList, a list of words
    thisReview = Hw1.read_line(fileLine)['text']
    tokenList = Hw1.tokenize(thisReview)
    stopList = Hw1.stopword(tokenList)

    #for each word in stoplist, compare to all terms in return list to
    #see if it exists, if it does add one to its second parameter, else
    #add it to the list as ["word", 0]
    for word in stopList:
        #if list not empty
        if not len(unStemmedList) == 1:   #for some reason I have to do this to see if list is empty, I'm assuming when it's empty it returns a length of 1 since I'm initializing it as a list of lists??
            print "List not empty."
            for innerList in unStemmedList:
                if innerList[0] == word:
                    print "Adding 1 to [" + word + ", " + str(innerList[1]) + "]"
                    innerList[1] = (innerList[1] + 1)
                else:
                    print "Adding [" + word + ", 0]"
                    unStemmedList.append([word, 0])
        else:
            print "List empty."
            unStemmedList.append([word, 0])
            print unStemmedList[len(unStemmedList)-1]

return stemmedList

最终输出最终为：

列表为空。 [ “测试1”，0] 列表不为空“

崩溃，列表索引超出范围错误，指向行if innerList[0] == word

Answer 1

假设stemmedList和unStemmedList相似

stemmedList = [[]]

您的列表列表中有一个空列表，它没有[0]。而只是将其初始化为：

stemmedList = []

Answer 2

您有a = [[]]

现在，当您在遇到第一个单词后附加到此列表时，您有

a = [ [], ['test', 0] ]

在下一次迭代中，您正在访问，不存在的空列表的第0个元素。

Answer 3

这不是更简单吗？

counts = dict()
def plus1(key):
    if key in counts:
        counts[key] += 1
    else:
        counts[key] = 1

stoplist = "t1 t2 t1 t3 t1 t1 t2".split()
for word in stoplist:
    plus1(word)

counts
{'t2': 2, 't3': 1, 't1': 4}

Python＆＃34;列表索引超出范围＆＃34;错误

3 个答案: