[FIXED] How do you copy data from a dataframe to another

Issue

I am having a difficult time getting the correct data from a reference csv file to the one I am working on.

I have a csv file that has over 6 million rows and 19 columns. I looks something like this : enter image description here

For each row there is a brand and a model of a car amongst other information. I want to add to this file the fuel consumption per 100km traveled and the type of fuel that is used.

I have another csv file that has the fuel consumption of every model of car that looks something like this : enter image description here

What I want to ultimately do is add the matching values of G,H, I and J columns from the second file to the first one.

Because of the size of the file I was wondering if there is another way to do it other than with a "for" or a "while" loop?

EDIT :

For example... The first df would look something like this

ID	Brand	Model	Other_columns	Fuel_consu_1	Fuel_consu_2
1	Toyota	Rav4	a	NaN	NaN
2	Honda	Civic	b	NaN	NaN
3	GMC	Sierra	c	NaN	NaN
4	Toyota	Rav4	d	NaN	NaN

The second df would be something like this

ID	Brand	Model	Fuel_consu_1	Fuel_consu_2
1	Toyota	Corrola	100	120
2	Toyota	Rav4	80	84
3	GMC	Sierra	91	105
4	Honda	Civic	112	125

The output should be :

ID	Brand	Model	Other_columns	Fuel_consu_1	Fuel_consu_2
1	Toyota	Rav4	a	80	84
2	Honda	Civic	b	112	125
3	GMC	Sierra	c	91	105
4	Toyota	Rav4	d	80	84

The first df may have many times the same brand and model for different ID's. The order is completely random.

Solution

Thank you for providing updates I was able to put something together that should be able to help you

#You drop these two columns because you won't need them once you join them to df1 (which is your 2nd table provided)
df.drop(['Fuel_consu_1', 'Fuel_consu_2'], axis = 1 , inplace = True)
#This will join your first and second column to each other on the Brand and Model columns 
df_merge = pd.merge(df, df1, on=['Brand', 'Model'])

Answered By - ArchAngelPwn

Answer Checked By - Katrina (PHPFixing Volunteer)