Execute equation from the elements of a list in python

Question

I have the following list and dataframe:

import pandas as pd
data = [[5, 10, 40], [2, 15, 70], [6, 14, 60]]
df = pd.DataFrame(data, columns=['A', 'B', 'C'])
lst = [5, '*', 'A', '+', 'C']

And I would like to create a code to execute the equation in the lst like 5 x A + C returning the following result:

data = [[65], [80], [90]]
dresult = pd.DataFrame(data, columns=['M'])

Is that possible?

Asked By: Thanasis

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Source

Answer 1

Yes. You simply do this:

import pandas as pd

data = [[5, 10, 40], [2, 15, 70], [6, 14, 60]]
df = pd.DataFrame(data, columns=['A', 'B', 'C'])
lst = [5, '*', 'A', '+', 'C']

expression = ' '.join(str(e) for e in lst)

dresult = pd.DataFrame()
dresult['M'] = df.eval(expression)

print(dresult)

which is:

Edit

In the multiindex case it would look like this:

import pandas as pd

data = [[5, 10, 40], [2, 15, 70], [6, 14, 60]]
index = pd.MultiIndex.from_tuples([('A', 'x'), ('B', 'x'), ('C', 'y')], names=['level_1', 'level_2'])
df = pd.DataFrame(data, index=index, columns=['Value_1', 'Value_2', 'Value_3'])

lst = [5, '*', 'Value_1', '+', 'Value_3']
expression = ' '.join(str(e) for e in lst)

dresult = pd.DataFrame()
dresult['Result'] = df.eval(expression)

print(dresult)

which would give you

                 Result
level_1 level_2        
A       x            65
B       x            80
C       y            90

You cn then clean your df as you see fit.

Answered By: Serge de Gosson de Varennes

Execute equation from the elements of a list in python

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