如何在numpy数组中找到最近的值?例子:
np.find_nearest(array, value)
如何在numpy数组中找到最近的值?例子:
np.find_nearest(array, value)
当前回答
稍微修改一下,上面的答案适用于任意维度的数组(1d, 2d, 3d,…):
def find_nearest(a, a0):
"Element in nd array `a` closest to the scalar value `a0`"
idx = np.abs(a - a0).argmin()
return a.flat[idx]
或者,写成一行:
a.flat[np.abs(a - a0).argmin()]
其他回答
import numpy as np
def find_nearest(array, value):
array = np.asarray(array)
idx = (np.abs(array - value)).argmin()
return array[idx]
使用示例:
array = np.random.random(10)
print(array)
# [ 0.21069679 0.61290182 0.63425412 0.84635244 0.91599191 0.00213826
# 0.17104965 0.56874386 0.57319379 0.28719469]
print(find_nearest(array, value=0.5))
# 0.568743859261
这是unutbu答案的矢量化版本:
def find_nearest(array, values):
array = np.asarray(array)
# the last dim must be 1 to broadcast in (array - values) below.
values = np.expand_dims(values, axis=-1)
indices = np.abs(array - values).argmin(axis=-1)
return array[indices]
image = plt.imread('example_3_band_image.jpg')
print(image.shape) # should be (nrows, ncols, 3)
quantiles = np.linspace(0, 255, num=2 ** 2, dtype=np.uint8)
quantiled_image = find_nearest(quantiles, image)
print(quantiled_image.shape) # should be (nrows, ncols, 3)
稍微修改一下,上面的答案适用于任意维度的数组(1d, 2d, 3d,…):
def find_nearest(a, a0):
"Element in nd array `a` closest to the scalar value `a0`"
idx = np.abs(a - a0).argmin()
return a.flat[idx]
或者,写成一行:
a.flat[np.abs(a - a0).argmin()]
对于那些搜索多个最接近的,修改接受的答案:
import numpy as np
def find_nearest(array, value, k):
array = np.asarray(array)
idx = np.argsort(abs(array - value))[:k]
return array[idx]
看到的: https://stackoverflow.com/a/66937734/11671779
下面是一个处理非标量“values”数组的版本:
import numpy as np
def find_nearest(array, values):
indices = np.abs(np.subtract.outer(array, values)).argmin(0)
return array[indices]
如果输入是标量,则返回数字类型(例如int, float)的版本:
def find_nearest(array, values):
values = np.atleast_1d(values)
indices = np.abs(np.subtract.outer(array, values)).argmin(0)
out = array[indices]
return out if len(out) > 1 else out[0]