Merge nested list items based on a repeating value

Question

Although poorly written, this code:

marker_array = [[\'hard\',\'2\',\'soft\'],[\'heavy\',\'2\',\'light\'],[\'rock\',\'2\',\'feather\'],[\'fast\',\'3\'], [\'turtl         


        

Answer 1

marker_array = [
    ['hard','2','soft'],
    ['heavy','2','light'],
    ['rock','2','feather'],
    ['fast','3'], 
    ['turtle','4','wet'],
]

data = {}

for arr in marker_array:
    if len(arr) == 2:
        arr.append('')

    (first, index, last) = arr
    firsts, lasts = data.setdefault(index, [[],[]])
    firsts.append(first)
    lasts.append(last)


results = []

for key in sorted(data.keys()):
    current = [
        " ".join(data[key][0]),
        key,
        " ".join(data[key][1])
    ]

    if current[-1] == '':
        current = current[:-1]

    results.append(current)



print results

--output:--
[['hard heavy rock', '2', 'soft light feather'], ['fast', '3'], ['turtle', '4', 'wet']]