Compare last element of a row to the rest of a row in pandas

Use DataFrame.lt for compare with last column selected by position:

df1 = df.iloc[:,:-1].lt(df.iloc[:, -1], axis=0)
#if want specify last column by label
#df1 = df.iloc[:,:-1].lt(df.col3, axis=0)
print (df1)
    col1   col2
0  False  False
1   True  False
2   True   True
3  False  False

Last if need 0,1 convert to integers by DataFrame.astype:

df1 = df.iloc[:,:-1].lt(df.iloc[:, -1], axis=0).astype(int)
#if want specify last column by label
#df1 = df.iloc[:,:-1].lt(df.col3, axis=0).astype(int)
print (df1)
   col1  col2
0     0     0
1     1     0
2     1     1
3     0     0

Your solution with numpy.where is possible use with DataFrame constructor:

arr = np.where(df.iloc[:,:-1].lt(df.col3, axis=0),1,0)
df1 = pd.DataFrame(arr, index=df.index, columns = df.columns[:-1])
print (df1)
   col1  col2
0     0     0
1     1     0
2     1     1
3     0     0