Convert single df column to list of lists

Question

How can you convert a single df column to a list of lists? using the df below, how can you return X to a list of lists.

df = pd.DataFrame({                
    'X' : [1,2,3,4,5,2,3,4,5,6],
    'Y' : [11,12,13,14,15,11,12,13,14,15],
    })

l = df['X'].values.tolist()

[1, 2, 3, 4, 5, 2, 3, 4, 5, 6]

Converting two columns is possible:

l = df.values.tolist()
[[1, 11], [2, 12], [3, 13], [4, 14], [5, 15], [2, 11], [3, 12], [4, 13], [5, 14], [6, 15]]

But I just want X.

[[1], [2], [3], [4], [5], [2], [3], [4], [5], [6]]

Answer 1

Some of these solutions seem overcomplicated. I believe this should do the job.

res_list = [[elem] for elem in df['X']]

Answer 2

If you want this output

[[1], [2], [3], [4], [5], [2], [3], [4], [5], [6]]

when starting with the input: [1,2,3,4,5,2,3,4,5,6]

then this should work fine

l = [[i] for i in df['X'].values.tolist()]

Answer 3

Try this:

 df['X'].apply(lambda x: [x]).tolist() 

output:

[[1], [2], [3], [4], [5], [2], [3], [4], [5], [6]]

Answer 4

IIUC

df.X.values[:,None].tolist()
Out[85]: [[1], [2], [3], [4], [5], [2], [3], [4], [5], [6]]