蟒蛇（numpy的）数组排序 [英] Python (Numpy) array sorting

问题描述

我有这个数组，命名为V，DTYPE的（'float64'）

I've got this array, named v, of dtype('float64'):

array([[  9.33350000e+05,   8.75886500e+06,   3.45765000e+02],
       [  4.33350000e+05,   8.75886500e+06,   6.19200000e+00],
       [  1.33360000e+05,   8.75886500e+06,   6.76650000e+02]])

...我已经从文件中使用np.loadtxt命令收购。我想的第一列的值后排序它，没有，保持在同一行列在一起的数字结构混合起来。使用v.sort（轴= 0）给我：

... which I've acquired from a file by using the np.loadtxt command. I would like to sort it after the values of the first column, without mixing up the structure that keeps the numbers listed on the same line together. Using v.sort(axis=0) gives me:

array([[  1.33360000e+05,   8.75886500e+06,   6.19200000e+00],
       [  4.33350000e+05,   8.75886500e+06,   3.45765000e+02],
       [  9.33350000e+05,   8.75886500e+06,   6.76650000e+02]])

...即放置在第一行第三列的最小数量等我宁愿希望这样的事情...

... i.e. places the smallest number of the third column in the first line, etc. I would rather want something like this...

array([[  1.33360000e+05,   8.75886500e+06,   6.76650000e+02],
       [  4.33350000e+05,   8.75886500e+06,   6.19200000e+00],
       [  9.33350000e+05,   8.75886500e+06,   3.45765000e+02]])

...，其中每行中的元素没有被相对彼此移动。

... where the elements of each line hasn't been moved relatively to each other.

推荐答案

尝试

v[v[:,0].argsort()]

（用 v 作为数组）。 v [：0] 是第一列，而 .argsort（）返回指数将排序的第一个柱。然后，这个顺序适用于使用先进的索引整个阵列。请注意，您得到一个数组的sorte副本。

(with v being the array). v[:,0] is the first column, and .argsort() returns the indices that would sort the first column. You then apply this ordering to the whole array using advanced indexing. Note that you get a sorte copy of the array.

我认识的到位数组排序的唯一方法是使用记录DTYPE：

The only way I know of to sort the array in place is to use a record dtype:

v.dtype = [("x", float), ("y", float), ("z", float)]
v.shape = v.size
v.sort(order="x")

这篇关于蟒蛇（numpy的）数组排序的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！