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

Question

I want to check every column in a dataframe whether it contains only numeric data. Specifically, my query is not about the datatype, but instead, I want to check every value in each column of the dataframe whether it's a numeric value.

How can I find this out?

Answer 1

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