how to change dtype in pandas code example

Example 1: change dataframe column type

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

Example 2: set column datatype pandas

df = pd.read_csv("weather.tsv", sep="\t",  
                 dtype={'Day': str,'Wind':int64})
df.dtypes