Question

我正在尝试使用Python读取包含数千个电子邮件地址的CSV文件，然后创建所有重复项的列表。这是我到目前为止的内容：

import csv

input_file='combined.csv'
original_list=[]
duplicate_list=[]

def readcsv(input_file):
    ifile = open(combined, "rU")
    reader = csv.reader(ifile, delimiter=";")

    rownum = 0
    for row in reader:
        original_list.append (row)
        rownum += 1

    ifile.close()
    original_list.sort()
    return original_list

(readcsv(input_file))

seen_set = set()
duplicate_set = set(x for x in original_list if x in seen_set or seen_set.add(x))
unique_set = seen_set - duplicate_set

print (duplicate_set)
print (unique_set)

Answer 1

而不是（出于注释中解释的原因，即使没有TypeError，它仍然是不好的python）：

seen_set = set()
duplicate_set = set(x for x in original_list if x in seen_set or seen_set.add(x))
unique_set = seen_set - duplicate_set

实际上，您需要的只是

# first just use set to grab all the possible elements (make lists hashable by
# passing through tuple) -- this is a set comprehension 
seen_set = {tuple(x) for x in original_list}

# the duplicates are just ones with counts > 1
duplicate_set = {t for t in seen_set if original_list.count(list(t)) > 1}

unique_set = seen_set - duplicate_set

您的函数也可以简单地写为

def readcsv(input_file):
    ifile = open(combined, "rU")
    reader = csv.reader(ifile, delimiter=";")
    return sorted(reader)  # don't mutate global variables!

original_list = readcsv(input_file)

TypeError：无法散列的类型：“列表”

1 个答案: