Concatenate cells into a string with separator pandas python

Question

Given the following:

df = pd.DataFrame({\'col1\' : [\"a\",\"b\"],
            \'col2\'  : [\"ab\",np.nan], \'col3\' : [\"w\",\"e\"]})

I would l

Answer 1

for row in xrange(len(df)):
    s = '*'.join(df.ix[row].dropna().tolist())
    print s