如何在SAS SGPLOT中为多分组系列设置自定义图例条目

问题原因 #

你当前代码中使用group=t会让每个series语句生成对应t值的多条线，但默认图例只会展示t的取值，而非系列名称。以下提供两种符合需求的调整方式：

方案1：显示7个系列标签（每个标签包含对应t的两种线型） #

将每个系列按t值拆分为两个独立的series语句，再通过keylegend的merge选项把同系列的两条线合并为一个图例项，同时保留颜色和线型区分：

proc sgplot data=natempdisdat3;
    by sex;
    
    /* 按t值分别绘制每个系列的实线/虚线，替换<t1>和<t2>为实际t的取值（比如0/1） */
    series x=age y=LE / name='LE_solid' lineattrs=(thickness=2 color=black pattern=solid) where=(t=<t1>);
    series x=age y=LE / name='LE_dash' lineattrs=(thickness=2 color=black pattern=dash) where=(t=<t2>);
    
    series x=age y=WLE / name='WLE_solid' lineattrs=(thickness=2 color=gray pattern=solid) where=(t=<t1>);
    series x=age y=WLE / name='WLE_dash' lineattrs=(thickness=2 color=gray pattern=dash) where=(t=<t2>);
    
    series x=age y=DFLE / name='DFLE_solid' lineattrs=(thickness=2 color=GREEN pattern=solid) where=(t=<t1>);
    series x=age y=DFLE / name='DFLE_dash' lineattrs=(thickness=2 color=GREEN pattern=dash) where=(t=<t2>);
    
    series x=age y=NHNWLE / name='NHNWLE_solid' lineattrs=(thickness=2 color=aquamarine pattern=solid) where=(t=<t1>);
    series x=age y=NHNWLE / name='NHNWLE_dash' lineattrs=(thickness=2 color=aquamarine pattern=dash) where=(t=<t2>);
    
    series x=age y=NHWLE / name='NHWLE_solid' lineattrs=(thickness=2 color=orange pattern=solid) where=(t=<t1>);
    series x=age y=NHWLE / name='NHWLE_dash' lineattrs=(thickness=2 color=orange pattern=dash) where=(t=<t2>);
    
    series x=age y=HWLE / name='HWLE_solid' lineattrs=(thickness=2 color=bippk pattern=solid) where=(t=<t1>);
    series x=age y=HWLE / name='HWLE_dash' lineattrs=(thickness=2 color=bippk pattern=dash) where=(t=<t2>);
    
    series x=age y=HNWLE / name='HNWLE_solid' lineattrs=(thickness=2 color=crimson pattern=solid) where=(t=<t1>);
    series x=age y=HNWLE / name='HNWLE_dash' lineattrs=(thickness=2 color=crimson pattern=dash) where=(t=<t2>);
 
    /* 合并同系列的两条线为一个图例项 */
    keylegend 
        "LE_solid" "LE_dash" / merge label='LE'
        "WLE_solid" "WLE_dash" / merge label='WLE'
        "DFLE_solid" "DFLE_dash" / merge label='DFLE'
        "NHNWLE_solid" "NHNWLE_dash" / merge label='NHNWLE'
        "NHWLE_solid" "NHWLE_dash" / merge label='NHWLE'
        "HWLE_solid" "HWLE_dash" / merge label='HWLE'
        "HNWLE_solid" "HNWLE_dash" / merge label='HNWLE'
        location=inside position=topright across=1;
run;

方案2：显示14个标签（每个标签对应「系列名称+t值」组合） #

先将宽格式数据转为长格式，再通过groupby组合系列和t值，自动生成带t值的图例标签，这种方式代码更简洁易维护：

第一步：转换数据为长格式 #

data long_data;
    set natempdisdat3;
    length series $20.;
    /* 逐个映射系列名称与对应数值 */
    series = 'LE'; value = LE; output;
    series = 'WLE'; value = WLE; output;
    series = 'DFLE'; value = DFLE; output;
    series = 'NHNWLE'; value = NHNWLE; output;
    series = 'NHWLE'; value = NHWLE; output;
    series = 'HWLE'; value = HWLE; output;
    series = 'HNWLE'; value = HNWLE; output;
    /* 保留需要的变量 */
    keep sex age t series value;
run;

第二步：绘制图形并生成带t值的图例 #

proc sgplot data=long_data;
    by sex;
    /* 用series+t作为分组，自动生成标签、匹配颜色和线型 */
    series x=age y=value / groupby=(series t)
        lineattrs=(thickness=2)
        /* 为每个系列指定固定颜色 */
        colorresponse=series colormodel=(black gray green aquamarine orange bippk crimson)
        /* 为每个t值指定线型 */
        patternresponse=t patternmodel=(solid dash)
        /* 生成带t值的图例标签 */
        legendlabel=catx(' (t=', t, ')');
    /* 设置图例位置 */
    keylegend / location=inside position=topright across=1;
run;

内容的提问来源于stack exchange，提问作者Raf