Randomly selecting different percentages of data in Python

Python beginner, here. I have a dataset with 101 rows which I have imported into Python (as a csv file) using Pandas. I essentially want to randomly generate a number between 0 and 1 and, based on the result, randomly select the percent equivalent from the dataset. So, for instance, a randomly generated number of 0.89 would require 89% of the data to be selected.

I also want to specify different percentages such that I have, for instance, 89%, 8% and 3% of the data randomly selected at once. This is so I can make different assumptions based on X% of data that has been selected (for instance, for 3% of rows selected print('A'), etc.). I finally want to simulate the whole thing several times and store the results.

I have been experimenting with different types of code, such as the df.sample(frac=0.89) and etc. but I'm not sure how to extend this to select different percentages at the same time.

My current code is:

import random
import pandas import pandas as pd

df = pd.read_csv(r'R_100.csv', encoding='cp1252')
df_1 = df['R_MD'].sample(frac=0.8889)
Total = df['PR_MD'].sum()
print(df_1, 'Total=', Total)


Any advice is much appreciated. Thanks in advance.

pandas

1 Answer
1

Here is something you can do, you need a function to do this every time.

import pandas as pd
df = pd.read_csv(r'R_100.csv', encoding='cp1252')


After you read the dataframe

def frac(dataframe, fraction, other_info=None):
"""Returns fraction of data"""
return dataframe.sample(frac=fraction)


here other_info can be specific column name and then call the function however many times you want

df_1 = frac(df, 0.3)


it will return you a new dataframe that you can use for anything you want, you can use this something like this as I infer from your example you are taking sum of a column

import random

def random_gen():
"""generates random number"""
return random.randint(0,1)




def print_sum(column_name):
"""Prints sum"""

# call the random_gen() to give out a number
rand_num = random_gen()

# pass the number as fraction parameter to frac()
df_tmp = frac(df, rand_num)

print(df_tmp[str(column_name)].sum())


Or if you want

but I'm not sure how to extend this to select different percentages at the same time.

Then just change the print_sum as follows

print_sum

def print_sum(column_name):
"""returns result for 10 iterations"""
# list to store all the result
results =

# selecting different percentage fraction
# for 10 different random fraction or you can have a list of all the fractions you want
# and then for loop over that list
for i in range(1,10):
# generate random number
fracr = random_gen()
# pass the number as fraction parameter to frac()
df_tmp = frac(df, fracr)
result.append(df_tmp[str(column_name)].sum())

return result


Hope this helps! Feedback is much appreciated :)

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