Comparing two data frames in python

Good evening, gentlemen.

I'm new to python, and programming. I'm trying to compare two different data frames, each one with the data of cars of a specific year. For now I've done the following:

year_08 = np.repeat('2008', 1061) # Variável com a quantidade de linhas do dataframe de 2008
year_18 = np.repeat('2018', 832) # Variável com a quantidade de linhas do dataframe de 2018

df_08['year'] = year_08 # Criando uma nova coluna com o ano no dataframe de 2008
df_18['year'] = year_18 # Criando uma nova coluna com o ano no dataframe de 2018

df = df_08.append(df_18, ignore_index=True) # Juntando os dois dataframes

I also saw the increase from year to year with the following:

fuel01 = df
fuel01 = fuel01[fuel01.fuel != 'Gasoline'] # Exclui as linhas que tem 'Gasoline' como dado
fuel01['year'].value_counts()

I just did not like the way it was, I wanted something, let's say, more professional. Any ideas how to do it?

Thank you.