How to browse pandas dataframe using row number eand column number

I am trying to browse my DF doing :

for row in range(len(DF)):
    for col in range(len(DF.columns)):
        print(DF[row][col])

but doing so throw :

KeyError: 0

I am wondering, how to browse a whole dataframe (including col name and excluding index) using only col number and row number.

>Solution :

If need select values by indices use DataFrame.iat/ DataFrame.iloc:

for row in range(len(DF)):
    for col in range(len(DF.columns)):
        print(DF.iat[row, col])
        #print(DF.iloc[row, col])

Better selecting by values of index, columns, it is same ouput if not duplicated index/columns values use DataFrame.at/DataFrame.loc:

for row in DF.index:
    for col in DF.columns:
        print(DF.at[row, col])
        #print(DF.loc[row, col])

BUT if possible use some vectorized solution the best is avoid looping.