Create a column with fixed values

Question

I am trying to create a new column in dataframe with values :

data = [4.91,4.93,5.02,4.93,4.82,4.57,4.49,4.57,4.54,4.52,4.56,4.73]

I have more than 50,000 rows in the dataframe and I want the values to be assigned randomly to the new column.

so the idea is that these values would be assigned randomly and repeated in the column.

I was thinking of using lambda function with this logic :

df.assign(value=lambda x: #function here)

Can anyone suggest any other way or a simpler way for the same? I am not able to understand the logic the function for assigning the values randomly.

Thanks

df['value'] = pd.np.random.choice(data, df.shape[0])?

Chris
– Chris

2019-09-06 06:01:30 +00:00
Commented Sep 6, 2019 at 6:01 — Chris
– Chris, Commented Sep 6, 2019 at 6:01

jezrael · Accepted Answer · 2019-09-06 06:08:35Z

4

Use numpy.random.choice with length of DataFrame:

import numpy as np

df = pd.DataFrame({
         'A':[7,8,9,4,2,3],
})

data = [4.91,4.93,5.02,4.93,4.82,4.57,4.49,4.57,4.54,4.52,4.56,4.73]

df = df.assign(value=np.random.choice(data, len(df)))
print (df)
   A  value
0  7   4.93
1  8   4.91
2  9   4.54
3  4   4.49
4  2   4.56
5  3   4.82

edited Sep 6, 2019 at 6:08

answered Sep 6, 2019 at 6:02

jezrael

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2 Comments

vp7 Over a year ago

This is putting other values as well instead of the values mentioned in array. Any reason as to why this is happening?

jezrael Over a year ago

@vp7 - hmmm, I think not possible, only reason should be float accuracy of values in list - so seems values are different.

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