How do I create a list from a data frame, containing each value of string column, multiplied by a second column? [duplicate]

Question

The question gets much clearer when an example is provided. I have a Data Frame with two columns, one of type string and one of type integer:

Col1   Col2
-------------
str1    2
str2    4
str3    1

now i need a list that contains the string in Col1 times the number in Col2, i.e. ['str1', 'str1', 'str2', 'str2', 'str2', 'str2', 'str3'].

What is the most efficient way to do so?

iDrwish · Accepted Answer · 2019-08-02 15:20:03Z

0

import numpy as np
np.repeat(df.Col1.values, df.Col2.values)

Output:

array(['str1', 'str1', 'str2', 'str2', 'str2', 'str2', 'str3'])

answered Aug 2, 2019 at 15:20

iDrwish

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