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MonkeyDLuffy
MonkeyDLuffy

Reputation: 558

Easier way for distributing elements of list to a new pandas DataFrame column in a specific ratio conditional on other column values of same dataframe

I have a pandas DataFrame df with multiple columns. Now I want to add a new column based on other column values. I found many answers for this on stack that includes np.where and np.select. However, in my case, for every if condition (every if/elif/else block), the new column has to choose among 3 values with a specific ratio. For example,

for i in range(df.shape[0]):
    if(df.iloc[i]['col1']==x):
        df.iloc[i]['new_col']= choose one value between l=['a','b','c'] in 0.3,0.3,0.4 ratio

that is, for all rows satisfying the condition in the if statement, the elements of list l should be distributed in the above mentioned ratio to new column.

Upvotes: 0

Views: 371

Answers (1)

Quang Hoang
Quang Hoang

Reputation: 150785

Try:

s = df['col1'] == x
df.loc[s, 'new_col'] = np.random.choice(['a','b','c'], 
                                        size=s.sum(), 
                                        p=[0.3,0.3,0.4])

Upvotes: 1

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