Pandas 学习笔记

使用merge时，如果没有指定 on = 哪一列，则默认以重叠列名当做链接键， 当然也可以按照多键连接，只需要’on’参数后传入多键列表即可

14.身份证发征地和当前行政区域查询

def get_location(id_number):
#     print(id_number)
    url = f'https://qq.ip138.com/idsearch/index.asp?userid={id_number}&action=idcard'
    headers = {
        'User-Agent':'Mozilla/5.0 (Linux; Android 6.0; Nexus 5 Build/MRA58N) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.128 Mobile Safari/537.36'
    }
    res = requests.get(url,headers = headers)
    html  = res.text.encode("ISO-8859-1").decode("utf-8")
    element = etree.HTML(html)
    try:
        issue_place = element.xpath("//div[@class='bd']/table/tbody/tr[5]/td[2]/p/text()")[0]
        current_place = element.xpath("//div[@class='bd']/table/tbody/tr[6]/td[2]/p/text()")[0]
    except Exception as e :
        current_place = issue_place
    return issue_place,current_place

df[['发证地区','行政区域']] = df.apply(lambda row:pd.Series(get_location(row['身份证号'])),axis=1)

15. 设置category

df["Status"] = df["Status"].astype("category")
 
df["Status"].cat.set_categories(["won","pending","presented","declined"],inplace=True)

16.获取除去某列的其他所有列

df.loc[:,df.columns != 'column_name' ]

17.查询只出现在left dataframe里的

(left.merge(right, on='key', how='left', indicator=True)
     .query('_merge == "left_only"')
     .drop('_merge', axis = 1))

18.根据第一个excel修改其他excel文件列表并 append在一起

dfs = []       
for i,f in enumerate(files):  # files 是excel 文件路径
    df = pd.read_excel(f)
    if i == 0:
        col = df.columns
    df.columns=col
    dfs.append(df)

19. 统计每列nan总数

df.isnull().sum()

文章均来自互联网如有不妥请联系作者删除QQ:314111741 地址：http://www.mqs.net/post/15287.html