count()
df.groupby(column_name).count()
Returns a DataFrame, with rows as groups, and all columns as the number of rows in each group.
- Note:
- All columns have the same value. It is advised to drop and rename the columns.
pets
| Index | Species | Color | Weight | Age |
|---|---|---|---|---|
| 0 | dog | black | 40 | 5 |
| 1 | cat | golden | 15 | 8 |
| 2 | cat | black | 20 | 9 |
| 3 | dog | white | 80 | 2 |
| 4 | dog | black | 25 | 0.5 |
| 5 | hamster | black | 1 | 3 |
| 6 | hamster | golden | 0.25 | 0.2 |
pets.groupby('Species').count()
| Index | ID | Color | Weight | Age |
|---|---|---|---|---|
| cat | 2 | 2 | 2 | 2 |
| dog | 3 | 3 | 3 | 3 |
| hamster | 2 | 2 | 2 | 2 |