Python assignment with optional result if not found

Question

I want to do an assignment which defaults to another if it fails.

this = {'one':1}
test = this['a'] if this['a'] else "Wololo"

I get a KeyError when I try this. Reason I need a one liner assignment is I have a minimum of five characters which may be in the dictionary and that requires five separate try blocks to check without returning an error.

.get is the real answer, but note that the ternary version would work if you made it this['a'] if 'a' in this else ... — jonrsharpe
– jonrsharpe, Commented Oct 30, 2015 at 11:40

EdChum · Accepted Answer · 2015-10-30 11:05:42Z

3

Use .get and pass a default value, if the key doesn't exist then the default value is returned:

In [267]:
this = {'one':1}
this.get('a','Wololo')

Out[267]:
'Wololo'

answered Oct 30, 2015 at 11:05

EdChum

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1 Comment

Remi Guan Over a year ago

And if you didn't select the second argument, it will return None instead a KeyError :)

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