[英]Python - Handling value errors
I am running an external function which should return a string - sometimes, however, this function fails and the string is empty. 我正在运行一个应返回字符串的外部函数-有时,此函数失败并且字符串为空。 The behaviour I would like is "if the string is empty(ie a value error will occur) instead print a '?'
我想要的行为是“如果字符串为空(即,将发生值错误),而不是打印'?' string to my CSV).
字符串到我的CSV)。
Here is my code : 这是我的代码:
outlist = output.split('\r\n') #splitting the string
outrank1 = outlist[1][outlist[1].index(':')+1:]
outrank2 = outlist[2][outlist[2].index(':')+1:]
print outrank1
print outrank2
print str(outlist[0])
print str(outlist[1])
print str(outlist[2])
csvout.writerow([str(outlist[0]), str(outrank1), str(outrank2)]) #writing,error here
Here is a sample of the bug I am encountering : 这是我遇到的错误的示例:
Traceback (most recent call last):
File "Methods.py", line 24, in <module>
outrank2 = outlist[2][outlist[2].index(':')+1:]
ValueError: substring not found
In this case, instead of an error I would like to save a '?' 在这种情况下,我想保存一个“?”而不是错误。 in outrank2.
排名第二。 How can I do this?
我怎样才能做到这一点?
you could wrap that in a try-except 您可以将其包装在try-except中
try:
outrank2 = outlist[2][outlist[2].index(':')+1:]
except ValueError:
outrank2 = "?"
try:
outrank1 = outlist[1][outlist[1].index(':')+1:]
except ValueError:
outrank1 = "?"
Use try, except method to check for value error. 使用try,除了方法检查值错误。
try:
outrank2 = outlist[2][outlist[2].index(':')+1:]
except ValueError:
outrank2 = "?"
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