Python Pandas获得独特的列数

Question

I'm new to Python, lots of JS experience and SQL, and everything I've found so far is counting number of uniques for each value, but all I want is a count of unique values in the column "Team"

uniqueCount= teamTable.groupby('Team').nunique()
print uniqueCount

But this only gives me the error "AttributeError: 'DataFrameGroupBy' object has no attribute 'nunique'"

Thought this would be simple enough to find, but honestly can't find the function

Date        ID  Team
1/1/2017    A   Bears
1/1/2017    A   Packers
1/1/2017    A   Lions
1/1/2017    B   Lions
1/3/2017    A   Packers

Answer 1

你可以用：

len(df.Team.unique())

Answer 2

You can use Series.nunique :

print (df.Team.nunique())
3

Answer 3

Using np.unique

np.unique(df.Team.values).size

3

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Followup to @Jeff's comment. He was spot on, @Bernies answer scales the best with my crude test. Might be indistinguishable form @jezrael's over all problem types.