根据分组中的键编辑pandas数据框字段

Question

Given this dataFrame:

import pandas as pd
  a = pd.DataFrame({
    'id': [1,2,3,4,5],
    'company_id': [11,11,22,33,55],
    'accSync': [True, False, False, False, True]
  })

I need to modify all rows for a given company_id based on the accSync field being True, meaning that if any row for a given company_id has a true in it, all rows for that company_id need to be updated to be true as well.

In this case, company_id 11 has a True in it and therefore row 2 should be updated to be 2, 11, True as well while rows 1,3,4,5 should remain unaffected.

I tried using a combination if groupby and any but aren't getting anywhere.

Answer 1

IIUC transform

a.groupby('company_id')['accSync'].transform('max')
Out[131]: 
0     True
1     True
2    False
3    False
4     True
Name: accSync, dtype: bool

---

Assign it back

a['accSync']= a.groupby('company_id')['accSync'].transform('max')

Answer 2

def checker(df):
    df["accSync"] = df["accSync"].any()
    return df

new_df = a.groupby(by="company_id").apply(checker)

Result:

   id  company_id  accSync
0   1          11     True
1   2          11     True
2   3          22    False
3   4          33    False
4   5          55     True