CODEWITHSUNDEEP
pythonpython-3.xdataframe
Raghu
Raghu

Reputation: 181

How to repeat single value as many times as other column in Python data frame?

I have to create Data frame with two columns in which df['col1'] rows should repeat as many times as other column df['col2']. This should repeat many times depends on list data.

Df:
     col1      col2

     Fruit     Apple
     Fruit     Mango
     Fruit     banana
     Place     US
     Place     UK
     Place     France 
     Place     India

Where I have data in following format List1 =["fruit", "place"] List2 =[["Apple", "Mango", "Banana"], ["US", "UK", "France", "India"]]

Note: not for loop approach bcs I have 2 million rows

Upvotes: 1

Views: 121

Answers (1)

Vaishali
Vaishali

Reputation: 38415

Here is a solution using numpy.repeat to repeat elements in list1 and itertools.chain.from_iterable to flatten the nested list,

list1 =['fruit', 'place']
list2 =[['Apple', 'Mango', 'Banana'], ['US', 'UK', 'France', 'India']]

import itertools
import numpy as np

l1 = np.repeat(np.array(list1), [len(i) for i in list2])
l2 = np.array(list(itertools.chain.from_iterable(list2)))
pd.DataFrame({'col1':l1, 'col2':l2})



    col1    col2
0   fruit   Apple
1   fruit   Mango
2   fruit   Banana
3   place   US
4   place   UK
5   place   France
6   place   India

Upvotes: 1

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