I have a pandas dataframe as follows:
a = pd.DataFrame({'col1': ('x','y'), 'col2':(1,2)})
I want to extract variable and associated values, such as,
x=1
y=2
How can I do that?
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Hello. You can use _values_: `a.values`. – user12628549 Dec 01 '20 at 06:19
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a.values or a.to_numpy will not help as I want two variables, x and y, to be created and their values get assigned. – anix-anirban Dec 01 '20 at 11:26
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It will give you the array of lists. You can extract everything from it. – user12628549 Dec 01 '20 at 11:56
1 Answers
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You can use exec to parse and execute Python code written in a string.
As an example exec('x=1') will create and instantiate variable x that you can use later in your code.
With this in mind the following will work
s = ','.join(a['col1']) + '=' + ','.join(a['col2'].astype('str'))
exec(s)
print(x,y)
produces
1 2
Here s is given as a string 'x,y=1,2'
If the values are say strings, you need to insert quote marks. Basically s needs to look like valid Python code. So for example you can do
a = pd.DataFrame({'col1': ('x','y'), 'col2':('red','green')})
s = ','.join(a['col1']) + '=' + ','.join(a['col2'].apply(lambda s:f'\'{s}\''))
exec(s)
print(x,y)
produces
red green
piterbarg
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Thanks, it almost works for me when the values are integer. What will be the modification when values are string, say, 'Red' and 'Green'? – anix-anirban Dec 01 '20 at 12:06
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@anix-anirban glad it helped! But do not overuse `exec`as it is generally considered bad practice, see [here](https://stackoverflow.com/questions/21553641/python-is-exec-always-bad-practice-and-if-so-why-not-deprecated#:~:text=As%20explained%20in%20other%20questions,issues%20and%20generally%20bad%20programming.). You can access those values in `df` using standard dtaframe methods so perhaps worth thinking about your design a bit more. – piterbarg Dec 01 '20 at 12:36