파이썬 - multi-column data array (list) sorting

>>> dist = [[25, 1],                                                                                                                                                                                               
            [12, 2],                                                                                                                                                                                                   
            [11, 3]]
... ... >>> 
>>> dist.sort(key=lambda a: a[0]) # key function only looks at first element in row ie column 0
>>> dist
[[11, 3], [12, 2], [25, 1]]
>>> dist = dist[0:2]  # take only the first 2 rows
>>> dist
[[11, 3], [12, 2]]