TypeError:'generator'对象没有属性'__getitem__'

Question

我写了一个应该返回字典的生成函数.但是当我尝试打印字段时,我收到以下错误

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

这是我的代码

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

Generator返回一个迭代器,你显然需要在它上面调用next.

你的最后一行代码应该是这样的 -

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,它会自动为我们做同样的事情.

Answer 2

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