excel填充日期

#在pandas中如果一列出现nan,则会认为他是float类型
import  pandas
from  datetime  import  datetime,timedelta

#关于月份加一的函数
def   add_month(d,md):  
    yd=md//12
    m=d.month+md%12
    if m!=12:
        yd=yd+m//12
        m=m%12
    return datetime(d.year+yd,m,d.day)

#header和sikprows作用一样
excel=pandas.read_excel('填充数据.xlsx',header=3,usecols='C:F',index_col=None,dtype={'id':str,'store':str,'data':str})
start=datetime(2020,2,10)

for  i in excel.index:
    excel.at[i,'id']=i+1
    excel['store'].at[i]='Yes' if i%2==0 else  'No'
    #excel['data'].at[i]=start  +  timedelta(days=i)   #加一天,最多只能加到天
    #excel['data'].at[i]=datetime(start.year+i,start.month,start.day)  #每一年加一
    excel['data'].at[i]=add_month(start,i)  #对每个月加一
excel.set_index('id',inplace=True)
print(excel)


timedelta函数:
>>>from datetime  import  timedelta
>>>time1=timedelta(seconds=23,minutes=35,hours=13,days=6)
>>>time2=timedelta(seconds=59,minutes=57,hours=18,days=8)
>>>time2-time1
datetime.timedelta(days=2, seconds=19356)  #返回时间差