Pythonで一次元配列と二次元配列の変換(numpyなし)

たまに忘れて1から考えるのでメモ．

sample.py

In [1]: a = [ chr(x) for x in range(65,65+16) ]

In [2]: print(a)
['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P']

In [3]: b = [ a[x:x+4] for x in range(0,len(a),4) ]

In [4]: print(b)
[['A', 'B', 'C', 'D'], ['E', 'F', 'G', 'H'], ['I', 'J', 'K', 'L'], ['M', 'N', 'O', 'P']]

In [5]: from itertools import chain

In [6]: c = [ x for x in chain.from_iterable(b) ]

In [7]: print(c)
['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P']

In [8]:

よくみかけるのはnumpyを使うパターンですが，このくらいの単純なリストなら組込みの範囲でできますしね．