python if elif else 区别

if  data_ori=='医疗':
    # 医疗
    df = pd.read_excel(path_apply + 'apply/YS_ZY_HZSQ_样例.xls', encoding='gbk', error_bad_lines=False)
    df=df[['HZMD']]
    df=df[~df['HZMD'].isnull()]

else:
    # 中国日报
    df = pd.read_csv(path_apply + 'apply/原始文本.txt', header=None, encoding='gbk')
return df

if  data_ori=='医疗':
    # 医疗
    df = pd.read_excel(path_apply + 'apply/YS_ZY_HZSQ_样例.xls', encoding='gbk', error_bad_lines=False)
    df=df[['HZMD']]
    df=df[~df['HZMD'].isnull()]

elif:
    # 中国日报
    df = pd.read_csv(path_apply + 'apply/原始文本.txt', header=None, encoding='gbk')
    return df


if 和 elif 的区别