pairplot (scatter plot matrix | 散点图矩阵)

SPairplot Create and customize pairplot (scatter plot matrix | 散点图矩阵)

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Basic usage : one matrix input

% Load Fisher's iris dataset (150 samples, 4 features, 3 species)
% 加载鸢尾花数据集（150个样本，4个特征，3个品种）
fisher = load("fisheriris.mat");
X = fisher.meas;            % 150×4 feature matrix / 特征矩阵
group = fisher.species;     % Species labels / 品种标签
label = {'sepal-length', 'sepal-width', 'petal-length', 'petal-width'};

% Create pairplot object with customized visualization
% 创建散点图矩阵对象，自定义可视化风格
SP = SPairplot(X, 'Group', group, 'DiagType', 1, 'UpperType', 9, 'LowerType', 2);
SP.draw();

% Set X-labels and Y-labels
% 设置 X 轴标签和 Y 轴标签
SP.setXLabelString(label);
SP.setYLabelString(label);

DiagType

UpperType and LowerType

Basic usage : two matrix input

% Generate synthetic data with three groups (150 samples, 6 features total)
% 生成包含三个分组的合成数据(150个样本，共6个特征)
P1 = mvnrnd([0,20,0,10,8,7], eye(6).*6, 50);
P2 = mvnrnd([10,5,15,0,4,2], eye(6).*8, 50);
P3 = mvnrnd([10,15,0,0,2,3], eye(6).*[3,9,2,1,4,4], 50);
G  = [ones(50,1)*1; ones(50,1)*2; ones(50,1)*3];  % Group labels / 分组标签

% Split into X (first 3 variables) and Y (last 3 variables)
% 拆分为 X(前3个变量)和 Y(后3个变量)
XY = [P1; P2; P3];
X = XY(:, 1:3);   
Y = XY(:, 4:6);   

% Create pairplot with two variable sets (X vs Y)
% 创建双变量集的散点图矩阵（X 与 Y 的对比）
% Note: When X and Y are both provided, only LowerType (off-diagonal below)
% is effective. Upper triangle and diagonal are automatically disabled.
% 注意：当同时输入 X 和 Y 时，仅 LowerType(下三角区域)生效，
% 上三角和对角线区域自动禁用。
SP = SPairplot(X, Y, 'Group', G, 'LowerType', 9);
SP.draw();

Properties setting for subplots

fisher = load("fisheriris.mat");
X = fisher.meas;            
group = fisher.species;     
label = {'sepal-length', 'sepal-width', 'petal-length', 'petal-width'};

SP = SPairplot(X, 'Group', group, 'DiagType', 1, 'UpperType', 9, 'LowerType', 2);

% set CData
SP.CData = [119,69,133; 56,108,155; 33,160,122] ./ 255;
SP.draw();

% Set X-labels and Y-labels
SP.setXLabelString(label);
SP.setYLabelString(label);


% Customize subplot appearance
% 自定义子图外观
SP.setAxes('Box','off', 'LineWidth',1.5, 'XGrid','on', 'YGrid','on')
SP.setXLabel('FontWeight','bold', 'Color',[0,0,.8])
SP.setYLabel('FontWeight','bold', 'Color',[.8,0,0])

Legend

fisher = load("fisheriris.mat");
X = fisher.meas;            
group = fisher.species; 
class = unique(group, 'stable');
label = {'sepal-length', 'sepal-width', 'petal-length', 'petal-width'};

SP = SPairplot(X, 'Group', group, 'DiagType', 1, 'UpperType', 9, 'LowerType', 2);
% set CData
SP.CData = [211, 43, 43;  61, 96,137; 249,206, 61;  76,103, 86;  80, 80, 80]./255;

SP.padding = [.08, .08, .2, .04];
SP.draw();

% Set X-labels and Y-labels
SP.setXLabelString(label);
SP.setYLabelString(label);


legend(SP.axMat{4, 4}, class, 'FontSize',17, 'Position',[.82, .88, .12, .08])