CODEWITHSUNDEEP
pythonpandas
Zac
Zac

Reputation: 323

make new column using value_counts in dataframe pandas

i am using below formula to get value count froma. column in a dataframe:

new_data = df['item'].value_counts()

which give me below result

Apples                    3
Green bananas             2
Bananas                   1
Oranges                   1

what i want is to get output for every item count in in new column like the below excel example

example

Any help or guidance is appreciated. Thank you

Upvotes: 2

Views: 4967

Answers (3)

jezrael
jezrael

Reputation: 862601

Use Series.map for your solution:

new_data = df['item'].value_counts()
df['Occurence'] = df['item'].map(new_data)

One row solution:

df['Occurence'] = df['item'].map(df['item'].value_counts())

If there is multiple columns:

cols = ['item','item1']
for c in cols:
    df[f'Occurence_{c}'] = df[c].map(df[c].value_counts())

 df.loc[len(df), cols] = df[cols].sum()

Or:

df = df.join(df[cols].apply(lambda x: x.map(x.value_counts())).add_prefix('Occurence_'))

Upvotes: 4

U13-Forward
U13-Forward

Reputation: 71570

Or by the index:

df.set_index('item').assign(count=df['item'].value_counts()).reset_index()

Since column assigning corresponds to the index, this way would do it.

Upvotes: 1

BENY
BENY

Reputation: 323226

Try with transform

df['new'] = df.groupby('item')['item'].transform('count')

Upvotes: 2

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