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  • 数组索引

    1 s = np.arange(13)**2
    2 s
    array([  0,   1,   4,   9,  16,  25,  36,  49,  64,  81, 100, 121, 144])

    1 s[0], s[4], s[-1]
    (0, 16, 144)

    1 s[1:5]
    array([ 1,  4,  9, 16])

    1 s[-4:]
    array([ 81, 100, 121, 144])

    1 s[-5::-2]
    array([64, 36, 16,  4,  0])

    1 r = np.arange(36)
    2 r.resize((6, 6))
    3 r
    array([[ 0,  1,  2,  3,  4,  5],
           [ 6,  7,  8,  9, 10, 11],
           [12, 13, 14, 15, 16, 17],
           [18, 19, 20, 21, 22, 23],
           [24, 25, 26, 27, 28, 29],
           [30, 31, 32, 33, 34, 35]])

    1 r[2, 2]
    14

    1 r[3, 3:6]
    array([21, 22, 23])

    1 r[:2, :-1]
    array([[ 0,  1,  2,  3,  4],
           [ 6,  7,  8,  9, 10]])

    1 r[-1, ::2]
    array([30, 32, 34])

    1 r[r > 30]
    array([31, 32, 33, 34, 35])

    1 r[r > 30] = 30
    2 r
    array([[ 0,  1,  2,  3,  4,  5],
           [ 6,  7,  8,  9, 10, 11],
           [12, 13, 14, 15, 16, 17],
           [18, 19, 20, 21, 22, 23],
           [24, 25, 26, 27, 28, 29],
           [30, 30, 30, 30, 30, 30]])







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  • 原文地址:https://www.cnblogs.com/zhengzhe/p/8511115.html
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