Pandas Useful skill

last update 20200823

Rename a columns

df.columns=['New Col 1' ,'New Col ','New Col 3']

  

Insert DataFrame to Mongo

from pymongo import MongoClient

def connect_mongo(db, collection, host='xxxxx', port=27017):

    client = MongoClient(host, port)

    db = client[db][collection]

    return db

 

db.insert_many(df.to_dict('records'))

 

 

#Query Data from Mongo to pandas

df=pd.DataFrame(list(db.find({}.{'_id':False}))

 

#Select time. First need to set the field to DateTime

df=df.set_index(pd.DateTimeindex(df1['date'])

 

#only need data in trading hour

df.between_time('9:00','16:30') 

 

 

df= df[df['date']>"2021-01-01"] 

 

 

Merge 2 DataFrame

 mpf=pd.merge(df,chk,left_on=['date'],right_on=['date'])

Locate first row date

df.iloc[0]

Display all row

pandas.set_option('display.max_rows', None)