CSV 以字节而非字符串形式返回 Python

Question

我收到的错误是：

_csv.Error: iterator should return strings, not bytes (did you open the file in text mode?)

在我的代码中的哪个位置以文本模式打开文件？

import csv
import urllib.request
import pymysql.cursors
connection = pymysql.connect(host='localhost',
                         user='',
                         password='',
                         db='mydb',
                         charset='utf8',
                         cursorclass=pymysql.cursors.DictCursor)
try:
    url = 'https://api.iextrading.com/1.0/stock/market/collection/sector?
    collectionName=Health%20Care&format=csv'
    response =  urllib.request.urlopen(url)
    csv_data = csv.reader(response)
    for row in csv_data:

    cursor.execute('INSERT INTO Financials (names, \
          classes, mark )' \
          'VALUES("%s", "%s", "%s")', 
          row)
finally:
    connection.close()

Answer 1

response =  urllib.request.urlopen(url)

此处 response returns bytes 对象上的迭代器，

如果您知道 csv 文件只是纯文本，您可以插入一个生成器理解来解码这些行：

csv_data = csv.reader(line.decode() for line in response)

或map（你不喜欢python 3 map当你可以在没有lambda的情况下使用它吗？）

csv_data = csv.reader(map(bytes.decode,response))

独立示例：

import urllib.request,csv

url = 'https://api.iextrading.com/1.0/stock/market/collection/sector?collectionName=Health%20Care&format=csv'
response =  urllib.request.urlopen(url)
for row in csv.reader(line.decode() for line in response):
    print(row)

现在您正在向 csv.reader 提供字符串列表，这将起作用。

示例输出：

['CAPR', 'Capricor Therapeutics Inc.', 'NASDAQ Capital Market', 'Healthcare', 'close', '0.9011', '1539955800519', '0.875', '1539979200341', '0.9011', '0.8702', '0.875', 'Close', 'October 19, 2018', '1539979200341', '96625', '', '', '', '0.875', '1539979200341', '0.9011', '0.0261', '0.02983', '1539954158310', '0.9011', '-0.0261', '-0.02896', '', '', '106532', '', '', '', '', '26905263', '-1.72', '3.19', '0.851', '-0.4716351592356688']
['AVDL', 'Avadel Pharmaceuticals plc', 'NASDAQ Global Market', 'Healthcare', 'close', '4.24', '1539955800643', '4.1', '1539979200312', '4.24', '4', '4.1', 'Close', 'October 19, 2018', '1539979200312', '78386', '', '', '', '4.1', '1539979200312', '4.2', '0.1', '0.02439', '1539892803066', '4.2', '-0.1', '-0.02381', '', '', '114387', '', '', '', '', '150734712', '-3.8', '11.93', '3.98', '-0.5579009090909092']

CSV 以字节而非字符串形式返回 Python

CSV Returning as Bytes not String Python

python

python-3.x

urllib

pymysql