1. list

找list中最大元素的索引:

aa = [1,2,3,4,5]
aa.index(max(aa))

2. numpy

2.1. 中位数

#求数组a的中位数
np.median(a)

#求数组a的四分位数
np.percentile(a, [25, 50, 75])

2.2. 找极值+索引

np.where(arr==3)

2.2.1. 寻找矩阵中最大的几个元素的index

def largest_indices(ary, n):
    """Returns the n largest indices from a numpy array."""
    flat = ary.flatten()
    indices = np.argpartition(flat, -n)[-n:]
    indices = indices[np.argsort(-flat[indices])]
    return np.unravel_index(indices, ary.shape)

2.3. 寻址、索引和遍历:

>>> x = np.array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
>>> x[1:7:2]
array([1, 3, 5])
>>> x[-2:10]
array([8, 9])
>>> x[-3:3:-1]
array([7, 6, 5, 4])

2.4. 打印

完整打印:

numpy.set_printoptions(threshold='nan')

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