python - CSV文件的map函数错误中使用的reduce函数

Question

import csv
import matplotlib.pyplot as plt
import functools
import operator
f=open("/Users/local/Documents/test_scripts/practice_2.csv",'r')
c=csv.reader(f)
names=["James","John","Harry","Jim"]
labels=[]
def namecount(n):
    count=[]
    for row in c:
        if row[5]==n:
            count.append(1)
    value=functools.reduce(operator.add,count)
    return value

l=map(namecount,names)
print(list(l))

我想要的输出是 [44,48,30,1]

但是当我运行代码时，出现以下错误

  File "/Users/290006411/PycharmProjects/Practice/pie_one.py", line 18, in <module>
    print(list(l))
  File "/Users/290006411/PycharmProjects/Practice/pie_one.py", line 14, in namecount
    value=functools.reduce(operator.add,count)
TypeError: reduce() of empty sequence with no initial value

不确定错误。

标签： pythonmapreducereduce