python - 简单的字符串连接失败

我有以下代码：

from yahoo_finance import Currency

symbolslist  = ["EURUSD","EURGBP","EURJPY","EURRUB","USDCAD","USDCHF","AUSUSD"]

for i in range(len(symbolslist)):
        symbol = symbolslist[i]
        nomisma = Currency(symbol).get_rate()

        quota = symbol + " = " + nomisma
        print quota

我得到的结果是：

EURUSD = 1.0891
EURGBP = 0.7322
EURJPY = 129.7440
EURRUB = 63.0560
USDCAD = 1.2614
USDCHF = 0.9622
Traceback (most recent call last):
  File "yahoopy.py", line 13, in <module>
    quota = symbol + " = " + nomisma
TypeError: cannot concatenate 'str' and 'NoneType' objects

我知道这个错误已经在this链接中讨论过了。
但我希望我可以克服这个错误，而不诉诸mysql。

最佳答案

问题是打字错误。而不是你写的。修复它，错误将消失：

symbolslist  = ["EURUSD","EURGBP","EURJPY","EURRUB","USDCAD","USDCHF","AUDUSD"]

不过，正如@BhargavRao建议的那样，使用AUDUSD来捕获此类错误仍然是一个好主意。

关于python - 简单的字符串连接失败，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/29331044/