pandas list unique values in column with count code example

Example 1: count unique pandas

df['column'].nunique()

Example 2: unique values in dataframe column count

df.groupby('mID').agg(['count', 'size', 'nunique']).stack()


             dID  hID  uID
mID                       
A   count      5    5    5
    size       5    5    5
    nunique    3    5    5
B   count      2    2    2
    size       2    2    2
    nunique    2    2    2
C   count      1    1    1
    size       1    1    1
    nunique    1    1    1

Example 3: python - count how many unique in a column

df['var_1'].nunique()   # How many unque values are present in a variable

Example 4: dataframe number of unique rows

1
# get the unique values (rows) by retaining last row
2
df.drop_duplicates(keep='last')