numpy模塊中的meshgrid函數(shù)用來生成網(wǎng)格矩陣，最簡(jiǎn)單的網(wǎng)格矩陣為二維矩陣

meshgrid函數(shù)可以接受 x1, x2,..., xn 等 n 個(gè)一維向量，生成 N-D 矩陣。

1 基本語法

meshgrid(*xi, **kwargs)

參數(shù)：

xi -?x1, x2,..., xn : array_like

返回值：

?X1, X2,..., XN : ndarray

2 示例(二維網(wǎng)格)

2.1 一個(gè)參數(shù)時(shí)

import numpy as np a = [1,2,3] b = np.meshgrid(a) print(b) # [array([1, 2, 3])]

當(dāng)只有一個(gè)參數(shù)時(shí)，返回值也只有一個(gè) b ，若寫兩個(gè)返回值??b, c = np.meshgrid(a)?則會(huì)報(bào)錯(cuò)。

2.2 兩個(gè)參數(shù)時(shí)

2.2.1 兩個(gè)參數(shù)長(zhǎng)度一致時(shí)

示例1?

import numpy as npa = [1,2,3] b = [9,8,7]c, d = np.meshgrid(a,b)print(c) print('-'*10) print(d)

運(yùn)行

[[1 2 3]
[1 2 3]
[1 2 3]]
----------
[[9 9 9]
[8 8 8]
[7 7 7]]

當(dāng)兩個(gè)參數(shù)長(zhǎng)度一致時(shí)（如長(zhǎng)度為 N ），則生成 N * N 維矩陣

示例2?

交換兩參數(shù)的順序

import numpy as npa = [1,2,3] b = [9,8,7]c, d = np.meshgrid(b,a)print(c) # [[9 8 7] # [9 8 7] # [9 8 7]] print(d) # [[1 1 1] # [2 2 2] # [3 3 3]]

交換兩個(gè)參數(shù)順序后，輸出結(jié)果發(fā)生了變化。

示例3

當(dāng)返回值值是兩個(gè)或兩個(gè)以上參數(shù)時(shí)，也可用一個(gè)參數(shù)來接受。

import numpy as np a = [1,2,3] b = [9,8,7] c = np.meshgrid(a,b) print(c) # 下面是打印出的結(jié)果+ # [array([[1, 2, 3], # [1, 2, 3], # [1, 2, 3]]), array([[9, 9, 9], # [8, 8, 8], # [7, 7, 7]])]

2.2.2 兩個(gè)參數(shù)長(zhǎng)度不一致時(shí)

import numpy as np a = [1,2,3] b = [9,8] c, d = np.meshgrid(a,b) print(c) # [[1 2 3] # [1 2 3]] print(d) # [[9 9 9] # [8 8 8]]

這是一個(gè) 2 * 3（2 行 3 列）

相當(dāng)于 b 由 行向量 變成了 列向量。

import numpy as np a = [1,2,3] b = [9,8] c, d = np.meshgrid(b, a) print(c) # [[9 8] # [9 8] # [9 8]] print(d) # [[1 1] # [2 2] # [3 3]]

3 示例（三維網(wǎng)格）

import numpy as npa = [1,2,3] b = [4,5,6] c = [7,8,9]x, y, z = np.meshgrid(a, b, c)print(x) # [[[1 1 1] # [2 2 2] # [3 3 3]] # # [[1 1 1] # [2 2 2] # [3 3 3]] # # [[1 1 1] # [2 2 2] # [3 3 3]]] print(y) # [[[4 4 4] # [4 4 4] # [4 4 4]] # # [[5 5 5] # [5 5 5] # [5 5 5]] # # [[6 6 6] # [6 6 6] # [6 6 6]]] print(z) # [[[7 8 9] # [7 8 9] # [7 8 9]] # # [[7 8 9] # [7 8 9] # [7 8 9]] # # [[7 8 9] # [7 8 9] # [7 8 9]]]

?

轉(zhuǎn)載于:https://www.cnblogs.com/gengyi/p/9420559.html

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