save the momery by reducing the data type

change_datatype.py

def change_datatype(df):
    int_cols = list(df.select_dtypes(include=['int']).columns)
    for col in int_cols:
        if ((np.max(df[col]) <= 127) and(np.min(df[col] >= -128))):
            df[col] = df[col].astype(np.int8)
        elif ((np.max(df[col]) <= 32767) and(np.min(df[col] >= -32768))):
            df[col] = df[col].astype(np.int16)
        elif ((np.max(df[col]) <= 2147483647) and(np.min(df[col] >= -2147483648))):
            df[col] = df[col].astype(np.int32)
        else:
            df[col] = df[col].astype(np.int64)

def change_datatype_float(df):
    float_cols = list(df.select_dtypes(include=['float']).columns)
    for col in float_cols:
        df[col] = df[col].astype(np.float32)