pythonpandasrandomintegerrange

Pandas: create new column in df with random integers from range


I have a pandas data frame with 50k rows. I'm trying to add a new column that is a randomly generated integer from 1 to 5.

If I want 50k random numbers I'd use:

df1['randNumCol'] = random.sample(range(50000), len(df1))

but for this I'm not sure how to do it.

Side note in R, I'd do:

sample(1:5, 50000, replace = TRUE)

Any suggestions?


Solution

  • One solution is to use numpy.random.randint:

    import numpy as np
    df1['randNumCol'] = np.random.randint(1, 6, df1.shape[0])
    

    Or if the numbers are non-consecutive (albeit slower), you can use this:

    df1['randNumCol'] = np.random.choice([1, 9, 20], df1.shape[0])
    

    In order to make the results reproducible you can set the seed with numpy.random.seed (e.g. np.random.seed(42))