pandas select row by index

df.iloc[[index]]

row_data = df.loc[ 'a' , : ]

dfObj.iloc[: , [0, 2]]

from pandas import DataFrame

boxes = {'Color': ['Green','Green','Green','Blue','Blue','Red','Red','Red'],
         'Shape': ['Rectangle','Rectangle','Square','Rectangle','Square','Square','Square','Rectangle'],
         'Price': [10,15,5,5,10,15,15,5]
        }

df = DataFrame(boxes, columns= ['Color','Shape','Price'])

select_color = df.loc[df['Color'] == 'Green']
print (select_color)

#select the first row 
df.iloc[1]
#select the first row and return the value in column ['Biologie']
candidate_df.iloc[1]['Biologie']