我目前正在尝试将值插入到列表中,该列表通过首先识别匹配项而打包到字典中.如果我有这样的字典：

{'12633': ['11-Mar-11', '26-Apr-11'], '11359': [], '11458': ['6-Aug-10'], '16335': ['29-May-13'], '11101': []}

我当前要执行的操作是逐行读取文件,并确定密钥是否存在于字典中.然后,确定值是否匹配或存在于字典键返回的列表中.此时,我想从列表中匹配值旁边的行中插入一个值.

with open('Pfa.csv', 'r') as f:
    for line in f:
        #split the line up into individual element - it's a csv file
        line = line.strip('/n')
        splitline = line.split(',')
        #check if the value in the file exists as a key in the dictionary
        if splitline[0] in Ndates:
            #iterate over the list in the dictionary
            for item in Ndates[splitline[0]]:
                #check if the item within the dictionary list is within this line in the file
                if item == splitline[1]:
                    #insert a vale from the file next to the value in the list within the dictionary
                    Ndates[splitline[0]].insert(Ndates[splitline[0]].index(item), splitline[4].strip('\n'))

不幸的是,由于某些我无法识别的原因,它似乎卡住了数据循环.只需将值添加到列表即可,但是它很杂乱,几乎有3k的值,我不想手工完成.

非常感谢您提供任何帮助,让我知道我要去哪里了.我觉得我做的效率很低,但是我愿意学习.

解决方法:

您正在遍历列表时对其进行修改.

一种解决方法：

        #iterate over the list in the dictionary
        for item in Ndates[splitline[0]][:]:

这将在迭代之前复制列表.

但是我建议重构：

import csv

with open('Pfa.csv') as f: #'r' is default
    for row in csv.reader(f):
        key = row[0]
        try:
            values = Ndates[key]
            i = values.index(row[1])
        except (KeyError, ValueError):
            pass
        else:
            values.insert(i, row[4]) #this will insert *before* the match; use i + 1 insert *after*