kevinya

將date變數轉成格式化的字串，將date變數做"年"  or "月" or "日"  的加減：

#取得日期參數
import pandas as pd
#保留變數種類為Date
beginDt = pd.datetime.now().date()
#strftime轉成字串型態
beginDt = pd.datetime.now().date().strftime('%Y %m %d').replace(' ','%2F')
endDt = pd.datetime.now().date() + pd.DateOffset(months=6)

print (pd.datetime.now())
print (pd.datetime.now().date())
print (pd.datetime.now().year)
print (pd.datetime.now().month)
print (pd.datetime.now().day)
print (pd.datetime.now().hour)
print (pd.datetime.now().minute)
print (pd.datetime.now().second)
print (pd.datetime.now().microsecond)

string.index,string.indexof,string.find,substring in string：

#這是string.indexof,string.index
print('----------這是要找substring的position的情況-------------')
str1 = "this is string example....wow!!!";
str2 = "exam"; 
print('透過str.index()，發現str2在str1的位置是:' + str(str1.index(str2)))
print('當str.index()找不到substring的時候，會出現exception')
print('----------這是要找substring的position的情況--------------------------')
if str1.find(str2) > -1:
    print('透過str.find()已確認str2的確存在於str1裡面！')
    print('但是str.find()最好還是用來取得substring的position就好')
    print('str2在str1的位置是' + str(str1.find(str2)))
print('-----------這是確認substring是否存在於原本string的情況-------------------------')  
if str2 in str1:
    print('透過 substring in string的語法，已確認str2存在於str1裡面')  
 

參考資料：
Why does Python throw an error when a substring is not found?
https://stackoverflow.com/questions/25916842/why-does-python-throw-an-error-when-a-substring-is-not-found
How to change the datetime format in pandas
https://stackoverflow.com/questions/38067704/how-to-change-the-datetime-format-in-pandas
Add months to a date in Pandas
https://stackoverflow.com/questions/46741423/add-months-to-a-date-in-pandas