Question

我运行代码时出现以下错误

    Traceback (most recent call last):
  File "E:\scanned\als course\12 15 14 the al project\index errot.py", line 80, in <module>
    sym_index = sym_list.index(y)
AttributeError: 'generator' object has no attribute 'index'
>>>

我对python很陌生，我认为＆＃34;我已正确声明列表并且列表具有索引属性？我只是不明白什么是错的任何帮助都会受到赞赏我也希望我能更好地格式化这个问题

数据的子集

    2015-08-04 02:14:05.249392,AA,0.0193103612,0.0193515212,0.0249713335,30.6542480634,30.7195875454,39.640763021,0.2131498442,29.0406746589,13524.5347810182,89,57,99
2015-08-04 02:14:05.325113,AAPL,0.0170506271,0.0137941891,0.0105915637,27.0670313481,21.8975963326,16.8135861893,-19.0986405157,-23.2172064279,21.5647072302,33,26,75
2015-08-04 02:14:13.596026,YUM,0.0150960249,0.0096451121,0.0059497165,23.9641966195,15.3111408421,9.4448821537,-36.1082656547,-38.3136615938,6.1077315656,10,11,70
2015-08-05 01:00:01.578356,AA,0.0195344666,0.0197647353,0.0216936719,31.0100044039,31.375544675,34.4376364665,1.178781745,9.7594856861,727.9298290159,83,53,98
2015-08-05 01:00:01.653702,AAPL,0.0182801429,0.0153930649,0.0129012765,29.0188272234,24.4357329651,20.4801414799,-15.7935199208,-16.1877341304,2.4960503525,55,30,69
2015-08-05 01:00:11.685967,YUM,0.015053783,0.0095630245,0.0045548817,23.8971396792,15.1808306936,7.2306505541,-36.4742772674,-52.3698623612,43.5802606239,11,10,74
2015-08-06 01:00:01.580982,AA,0.016405504,0.0187336551,0.0138878945,26.0429302344,29.7387555321,22.0463490932,14.1912805682,-25.8666050455,-282.2711130351,50,69,35
2015-08-06 01:00:01.657591,AAPL,0.0177744137,0.0123407978,0.0155526393,28.2160070183,19.590409183,24.6890494178,-30.5698741487,26.0262059213,-185.1367781062,97,9,44
2015-08-06 01:00:14.071073,YUM,0.0134016613,0.009754587,0.0046291687,21.2744777757,15.4849268147,7.3485774914,-27.2135984817,-52.543673087,93.07874011,19,12,83
2015-08-07 01:00:02.111758,AA,0.0167336443,0.0195330063,0.0157903576,26.5638368026,31.0076862614,25.0664156097,16.7289442857,-19.1606384353,-214.5358494121,42,79,34
2015-08-07 01:00:02.426008,AAPL,0.0172853837,0.01222536,0.0159302942,27.4396959903,19.4071573379,25.2885580713,-29.2734243675,30.3053179346,-203.525018304,96,10,35
2015-08-07 01:00:20.003695,YUM,0.0113498677,0.007539233,0.0090156499,18.0173564022,11.9681613499,14.3119005831,-33.5742653767,19.583118615,-158.3277650167,69,8,34

导致错误的代码

import csv
from datetime import datetime

num_sym = 100
num_days = 252

sym_list = []
date_list = []
sym_index = 0
date_index = 0




hvabs_tab = [[0 for x in range(num_sym)] for y in range(num_days)]
dates_t = []



def dedupe(items):
    seen = set()
    for item in items:
        if item not in seen:
            yield item
            seen.add(item)

    return item



def parse_ymd(s):

    date_bit = s.split('-')

    long_date = date_bit[0]+":" + date_bit[1]+":"  + date_bit[2]  # formatted 2015:08:05

    #print('y',date_bit[0],'m',date_bit[1],'d',date_bit[2],'all',date_bit)
    #y 2015 m 08 d 04 all ['2015', '08', '04']

    return long_date # formatted 2015:08:05





with open('hvanal2015s.csv') as f:

    f_csv = csv.reader(f)

    for x in f_csv:
        for i,y in enumerate(x):
            if i == 1 :
                sym_list.append(y) # grabbing ALL the symbols shoving them in list

            if i == 0 :
                date_line = str(x[0])
                date_t = date_line.split()
                just_date = parse_ymd(date_t[0])
                date_list.append(just_date) # grabbing ALL dates shoving them in list




    sym_list = dedupe(sym_list)

    date_list = dedupe(date_list)

    print('sym list final',*sym_list)
    print('date list final',*date_list)
    print('---------------------')



    f.seek(0) # resetting the csv iterator to top of file to process the ranks now we have
                  # the lists for sym and dates populated

    for day_data in f_csv:
        for i,y in enumerate(day_data):
            if i == 1 : # found symbol
               sym_index = sym_list.index(y)
               print('y and sym index',y,sym_index)



           # if i == 0 : # found related date 
               #date_index = date_list.index(y)
               # print('y and date index',y,date_index)

Answer 1

注意dedupe：

的定义

def dedupe(items):
    seen = set()
    for item in items:
        if item not in seen:
            yield item
            seen.add(item)

    return item

查看yield关键字？这使得返回值为generator（可迭代），但它不是list。您可以使用内置list callable从生成器轻松构造list：

sym_list = list(dedupe(sym_list))

^{另外，请注意您的dedupe生成器函数有一个return语句，但除了欺骗您的代码读者以外，它并没有真正做任何事情，而是认为{{1 }}不是生成器： - ）}

python 3.4 list index属性抛出错误

1 个答案: