import pandas as pd
df = pd.DataFrame({'user': [1, 2,
3, 4],
'occupation': [380, 380, 24, 26]})
dic = df.groupby('user')['occupation'].apply(list).to_dict()
# for d in dic:
# print(d, dic[d][0])
keys = df['occupation'].unique().astype(int)
idx = {key: [] for key in keys}
for i in range(1, len(dic)+1):
occ = int(dic[i][0])
idx[occ].append(i)
for i in idx:
print(i, idx[i])
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