i don't get mongodb collection shard key with pymongo

Question

i need to copy db meta to anthoer , i have done copy index, but i couldn't get the shard key of colleciont , so what should I do ? can you give me a example ?

cnn = pymongo.MongoClient(mongo_uri)
dbadmin = cnn.admin
dbadmin.command('enableSharding',new_db_nm)
dbadmin.command({'shardCollection': coll1, 'key': {'key1': 'hashed'}})

i want get the key1 from old_db

Answer 1

You can do that by specifying the date format in pandas. Remember pandas by default will show dates as year-month-date.

df.index=pd.to_datetime(df.index,format='%d/%m/%Y')

#output:
            value
2020-03-18      0
2020-03-19      3
2020-03-20      5
2020-03-21      1
2020-03-22      6
2020-03-23      3
2022-01-11    558
2022-01-12      0

If you want to verify that's reading correctly the month and the day you can create columns with day and month number. Notice it's reading the last row as January 12

df.index=pd.to_datetime(df.index,format='%d/%m/%Y')
df['dates_str']=df.index.map(lambda x: x.strftime('%b %d %Y'))
df['day']=df.index.day
df['month']=df.index.month
df['year']=df.index.year

#output
            value    dates_str  day  month  year
2020-03-18      0  Mar 18 2020   18      3  2020
2020-03-19      3  Mar 19 2020   19      3  2020
2020-03-20      5  Mar 20 2020   20      3  2020
2020-03-21      1  Mar 21 2020   21      3  2020
2020-03-22      6  Mar 22 2020   22      3  2020
2020-03-23      3  Mar 23 2020   23      3  2020
2022-01-11    558  Jan 11 2022   11      1  2022
2022-01-12      0  Jan 12 2022   12      1  2022