join on column pandas
# df1 as main df and use the feild from df2 and map it into df1
df1.merge(df2,on='columnName',how='left')join on column pandas
# df1 as main df and use the feild from df2 and map it into df1
df1.merge(df2,on='columnName',how='left')pandas merge python
import pandas as pd
df1 = pd.DataFrame({'lkey': ['foo', 'bar', 'baz', 'foo'],
'value': [1, 2, 3, 5]})
df2 = pd.DataFrame({'rkey': ['foo', 'bar', 'baz', 'foo'],
'value': [5, 6, 7, 8]})
df1.merge(df2, left_on='lkey', right_on='rkey')merge dataframe pandas
>>> df1.merge(df2, left_on='lkey', right_on='rkey')
lkey value_x rkey value_y
0 foo 1 foo 5
1 foo 1 foo 8
2 foo 5 foo 5
3 foo 5 foo 8
4 bar 2 bar 6
5 baz 3 baz 7merge pandas
select * from bricks, colours;merge pandas
select * from bricks;
select * from colours;merge pandas
create table bricks (
brick_id integer,
colour varchar2(10)
);
create table colours (
colour_name varchar2(10),
minimum_bricks_needed integer
);
insert into colours values ( 'blue', 2 );
insert into colours values ( 'green', 3 );
insert into colours values ( 'red', 2 );
insert into colours values ( 'orange', 1);
insert into colours values ( 'yellow', 1 );
insert into colours values ( 'purple', 1 );
insert into bricks values ( 1, 'blue' );
insert into bricks values ( 2, 'blue' );
insert into bricks values ( 3, 'blue' );
insert into bricks values ( 4, 'green' );
insert into bricks values ( 5, 'green' );
insert into bricks values ( 6, 'red' );
insert into bricks values ( 7, 'red' );
insert into bricks values ( 8, 'red' );
insert into bricks values ( 9, null );
commit;Copyright © 2021 Codeinu
Forgot your account's password or having trouble logging into your Account? Don't worry, we'll help you to get back your account. Enter your email address and we'll send you a recovery link to reset your password. If you are experiencing problems resetting your password contact us
