def df64bitto32bit(tbl):
    newtbl = pd.DataFrame(index=tbl.index)
    for colname in tbl.columns:
        newtbl[colname] = series64bitto32bit(tbl[colname])
    return newtbl
Convert a Pandas dataframe from 64 bit types to 32 bit types to save
dataset/ETHPy150Open UDST/urbansim/urbansim/utils/misc.py/df64bitto32bit