How to determine whether a column/variable is numeric or not in Pandas/NumPy?

Question

Is there a better way to determine whether a variable in Pandas and/or NumPy is numeric or not ?

I have a self defined

Answer 1

How about just checking type for one of the values in the column? We've always had something like this:

isinstance(x, (int, long, float, complex))

When I try to check the datatypes for the columns in below dataframe, I get them as 'object' and not a numerical type I'm expecting:

df = pd.DataFrame(columns=('time', 'test1', 'test2'))
for i in range(20):
    df.loc[i] = [datetime.now() - timedelta(hours=i*1000),i*10,i*100]
df.dtypes

time     datetime64[ns]
test1            object
test2            object
dtype: object

When I do the following, it seems to give me accurate result:

isinstance(df['test1'][len(df['test1'])-1], (int, long, float, complex))

returns

True