Looping Through And Comparing Values In Different Dataframes

I have two dataframes:

df1:

df2:

I want a third result dataframe df3 such that if the score in df2 is between the lower and upper values of df1, that row gets assigned the corresponding rank from df1

Try this.

df1 = pd.DataFrame( [[0,7,'first'],[8,14,'second'],[15,23,'third']], columns = ['Lower', 'Upper', 'Rank'])
df2 = pd.DataFrame( [5,3,8,13,20], columns = ['Score'])

result = []
for index, val in df2.iterrows():
    for id, rank in df1.iterrows():
        if val['Score'] >= rank['Lower'] and val['Score'] <= rank['Upper']:
            result.append(rank['Rank'])
            break

df_result = pd.DataFrame(columns = ['Score','Rank'])
df_result['Score'] = df2['Score']
df_result['Rank'] = result