我试图对列表的频率进行直方图显示，列表如下：
> x[1:15,]
X x
1 1 JUAN DOMINGOGONZALEZDELGADO
2 2 FRANCISCO JAVIERVELARAMIREZ
3 3 JUAN CARLOSPEREZMEDINA
4 4 ARMANDOSALINASSALINAS
5 5 JOSE FELIXZAMBRANOAMEZQUITA
6 6 GABRIELMONTIELRIVAS
7 7 DONACIANOSANCHEZHERRERA
8 8 JUAN MARTINXHUERTA
9 9 ALVARO ALEJANDROGONZALEZRAMOS
10 10 OMAR ROMANCASTAÑEDALOPEZ
11 11 IGNACIOBUENOCANO
12 12 RAFAELBETANCOURTDELGADO
13 13 LUIS ALBERTOCASTILLOESCOBEDO
14 14 VICTORHERNANDEZGONZALEZ
15 15 FATIMAROMOTORRES
为此，我将其更改为频率表，如下所示：
> y[1:15,]
X x Freq
1 1 15
2 2 JULIO CESAR ORDAZFLORES 1
3 3 MARCOS ANTONIOCUEVASNAVARRO 1
4 4 DULEY DILTON TRIBOUILLIERLOARCA 1
5 5 ANTONIORAMIREZLOPEZ 2
6 6 BRAYAN ALEJANDROOJEDARAMIREZ 1
7 7 JOSE DE JESUSESCOTOCORTEZ 1
8 8 AARONFLORESGARCIA 1
9 9 ABIGAILNAVARROAMBRIZ 1
10 10 ABILENYRODRIGUEZORTEGA 1
11 11 ABRAHAMHERNANDEZRAMIREZ 1
12 12 ABRAHAMPONCEALCANTARA 1
13 13 ADRIAN VAZQUEZ BUSTAMANTE 2
14 14 ADRIANHERNANDEZBERMUDEZ 28
15 15 ALAN ORLANDOCASTILLALOPEZ 11
当我尝试hist(x)或hist(x[,2])时，我得到：
Error in hist.default(x) : 'x' must be numeric
如果我尝试hist(y[,3])，会得到一个奇怪的直方图，这是不希望的，那么现在如何制作名称列表频率的直方图？