Python 类型错误：字符串索引必须是整数，而不是 str
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TypeError: string indices must be integers, not str
提问by imoum
import urllib2
currency = 'EURO'
req = urllib2.urlopen(' http://rate-exchange.appspot.com/currency?from=USD&to='+ currency +'')
result = req.read()
print p
p = result["rate"]
print int(p)
this what i got with print presult = {"to": "EURO", "rate": 0.76810814999999999, "from": "USD"}
这就是我得到的print p结果 = {"to": "EURO", "rate": 0.76810814999999999, "from": "USD"}
but I have the error:
但我有错误：
TypeError: string indices must be integers, not str
回答by DSM
The result of your .read()call isn't a dictionary, it's a string:
您的.read()调用结果不是字典，而是字符串：
>>> import urllib2
>>> currency = "EURO"
>>> req = urllib2.urlopen('http://rate-exchange.appspot.com/currency?from=USD&to='+ currency +'')
>>> result = req.read()
>>> result
'{"to": "EURO", "rate": 0.76810814999999999, "from": "USD"}'
>>> type(result)
<type 'str'>
It looks like the result is a JSON-encoded dict, and so you can use something like
看起来结果是一个 JSON 编码的字典，所以你可以使用类似的东西
>>> import json, urllib2
>>> currency = "EURO"
>>> url = "http://rate-exchange.appspot.com/currency?from=USD&to=" + currency
>>> response = urllib2.urlopen(url)
>>> result = json.load(response)
>>> result
{u'to': u'EURO', u'rate': 0.76810815, u'from': u'USD'}
>>> type(result)
<type 'dict'>
>>> result["rate"]
0.76810815
>>> type(result["rate"])
<type 'float'>
[Note that I left your url construction alone, although I think there are better ways to handle adding parameters like fromand to. Also note that under the circumstances it doesn't make sense to convert the conversion rate into an int.]
[请注意，我没有考虑您的 url 构造，尽管我认为有更好的方法来处理添加from和to. 另请注意，在这种情况下，将转换率转换为int.]是没有意义的。]
