Python pandas: Getting the locations of a value in dataframe

Question

Suppose I have the following dataframe:

   'a' 'b'
0   0   0
1   1   0
2   0   1
3   0   1

Is there a way I could get the index/column values for which a specific value exists? For example, something akin to the following:

values = df.search(1)

would have values = [(1, 'a'), (2, 'b'), (3, 'b')].

Answer 1

df[df == 1].stack().index.tolist()

yields

[(1, 'a'), (2, 'b'), (3, 'b')]