How to check if a pandas dataframe contains only numeric values column-wise?

Question

You can check that using to_numeric and coercing errors:

pd.to_numeric(df['column'], errors="coerce").notnull().all()

For all columns, you can iterate through columns or just use apply

df.apply(lambda s: pd.to_numeric(s, errors="coerce").notnull().all())

E.g.

df = pd.DataFrame({'col' : [1,2, 10, np.nan, 'a'], 
                   'col2': ['a', 10, 30, 40 ,50],
                   'col3': [1,2,3,4,5.0]})

Outputs

col     False
col2    False
col3     True
dtype: bool