change data type pandas code example

Example 1: change dataframe column type

>>> df.astype({'col1': 'int32'}).dtypes
col1    int32
col2    int64
dtype: object

Example 2: convert a pandas column to int

# convert Series
my_series = pd.to_numeric(my_series)

# convert column "a" of a DataFrame
df["a"] = pd.to_numeric(df["a"])