TypeError:“generator”对象没有属性“getitem”

Question

我写了一个生成函数，它应该返回一个字典。但是，当我试图打印一个字段时，会出现以下错误

print row2['SearchDate']
TypeError: 'generator' object has no attribute '__getitem__'

这是我的密码

from csv import DictReader
import pandas as pd
import numpy as np


def genSearch(SearchInfo):
    for row2 in DictReader(open(SearchInfo)):
        yield row2

train = 'minitrain.csv'

SearchInfo = 'SearchInfo.csv'

row2 = {'SearchID': -1}

for row1 in DictReader(open(train)):
    if 'SearchID' in row1 and 'SearchID' in row2 and row1['SearchID'] == row2['SearchID']:
        x = deepcopy( row1 )
        #x['SearchDate'] = row2['percent']
        x.update(row2)    
        print 'new'
        print x
    else: 
        #call your generator
        row2 = genSearch(SearchInfo)
        print row2['SearchDate']

Answer 1

生成器必须是迭代器，而不是iterable。Iterables包含 __item__()和__getitem__()方法，而迭代器包含next()/__next__()方法（python版本2.x/3.x）。

Answer 2

生成器返回一个迭代器，显式地需要对其调用next。

最后一行代码应该是-

rows_generator = genSearch(SearchInfo)
row2 = next(rows_generator, None)
print row2['SearchDate']

理想情况下，我们在循环中使用迭代器，它会自动为我们执行相同的操作。