import module within python lambda function

Question

Is it possible to import module within a python lambda function? For example, i have a lambda function which requires to import math

import math
is_na_yes_no = lambda x: 'Yes' if math.isnan(x) else 'No'

How can I include the import math statement within the lambda function?

To clarify, I have a scenario that need to put some lambda functions in a config file and evaluate the function in some other python files, exmample:

{
  "is_na_yes_no" = "lambda x: 'Yes' if math.isnan(x) else 'No'"
}

In this case, the python file that evaluating those lambda functions need to all modules required.

so for each iterable you want to import again and again, this is bad — sahasrara62
– sahasrara62, Commented Oct 4, 2019 at 9:32
Yay codegolfing.. lambda x:'Yes'if __import__('math').isnan(x)else'No' — L3viathan
– L3viathan, Commented Oct 4, 2019 at 9:47
Why do they have to be lambda functions? Why can't they be real functions? — Aran-Fey
– Aran-Fey, Commented Oct 4, 2019 at 9:50

henrywongkk · Accepted Answer · 2019-10-04 10:07:16Z

3

Thanks @L3viathan for the answer.

Here is same thing without having to import math in the module.

is_na_yes_no = lambda x: 'Yes' if __import__('math').isnan(x) else 'No'

It highlights the flexibility of python -- __import__ feature can be used in lambda functions instead of having them written out before hand.

answered Oct 4, 2019 at 10:07

henrywongkk

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