如何按一列字典顺序对 2D numpy 数组进行排序？

Question

如何对具有 2 个元素的 numpy 二维数组进行排序：例如我有：

[['0.6435256766173603' 'some text']
 ['0.013180497307149886' 'some text2']
 ['0.017696632827641112' 'some text3']]  
I need:
[['0.6435256766173603' 'some text']
 ['0.017696632827641112' 'some text3']
 ['0.013180497307149886' 'some text2']]

我尝试了np.argsort、np.sort，但是没有用！任何帮助将不胜感激

Answer 1

假设您希望您的数组按第 0 列进行词法排序，np.argsort 就是您想要的。

out = x[np.argsort(x[:, 0])[::-1]]
print(out)

array([['0.6435256766173603', 'some text'],
       ['0.017696632827641112', 'some text3'],
       ['0.013180497307149886', 'some text2']],

Answer 2

a = np.array([['0.6435256766173603', 'some text'],
              ['0.013180497307149886', 'some text2'],
              ['0.017696632827641112', 'some text3']])

a[a[:, 0].argsort()[::-1]]

应该屈服

array([['0.6435256766173603', 'some text'],
       ['0.017696632827641112', 'some text3'],
       ['0.013180497307149886', 'some text2']],
      dtype='|S20')

分解：

# the first column of `a`
a[:, 0]  

# sorted indices of the first column, ascending order
a[:, 0].argsort()  # [1, 2, 0]

# sorted indices of the first column, descending order
a[:, 0].argsort()[::-1]  # [0, 2, 1]

# sort `a` according to the sorted indices from the last step
a[a[:, 0].argsort()[::-1]]

如何按一列字典顺序对 2D numpy 数组进行排序？

How to sort a 2D numpy array lexicographically by one column?

python

arrays

sorting

numpy

lexicographic