排序numpy的字符串数组负数？ [英] Sort numpy string array with negative numbers?

问题描述

我在整理有数字作为一个字符串数组numpy的一个问题。我需要保持这些字符串，因为有整数后等字样。

I'm having a problem sorting a numpy array that has numbers as strings. I need to keep these as strings because there are other words after the integers.

它的排序负数以相反的顺序：

It's sorting negative numbers in reverse order:

>>> import numpy as np
>>> a = np.array(["3", "-2", "-1", "0", "2"])
>>> a.sort()
>>> a
array(['-1', '-2', '0', '2', '3'], dtype='|S2')

我本来期望的输出是：

I would have expected the output to be:

array(['-2', '-1', '0', '2', '3'], dtype='|S2')

有什么建议？

推荐答案

您可以使用自然排序：

import numpy as np
import re

def atoi(text):
    try:
        return int(text)
    except ValueError:
        return text

def natural_keys(text):
    '''
    alist.sort(key=natural_keys) sorts in human order
    http://nedbatchelder.com/blog/200712/human_sorting.html
    '''    
    return [ atoi(c) for c in re.split('([-]?\d+)', text) ]

a = np.array(["3", "-2", "-1", "0", "2", "word"])
print(sorted(a,key=natural_keys))
# ['-2', '-1', '0', '2', '3', 'word']

a = np.array(["3", "-2", "-1", "0", "2", "word", "-1 word", "-2 up"])
print(sorted(a,key=natural_keys))
# ['-2', '-2 up', '-1', '-1 word', '0', '2', '3', 'word']

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