R中多列的小提琴图

如何解决R中多列的小提琴图

我有以下数据框，以制表符分隔

V1  V2  V3  V4  V5  V6  V7  V8  V9  V10 V11 V12
11.12196492 7.085393647 5.146473348 9.258024668 9.357336047 8.79735463  10.38696668 11.49223523 11.79250704 8.118257428 7.396105825 11.98250891
7.166352227 8.519792305 8.836730679 13.07257854 10.10185235 6.74028219  11.74429294 5.963815644 4.732228284 11.7812365  10.85146038 7.846785927
11.19680038 10.69257229 8.672686746 10.06575493 11.58330501 10.13549117 8.262434229 14.57539851 10.96055328 10.25700577 8.144988759 6.025398663
8.4472141   14.43048423 7.777374247 12.42507977 9.858789629 8.100075323 9.054775806 7.679307189 9.207057826 11.2365648  10.52810623 12.01360463
10.86340307 10.23838217 8.323361284 8.361738417 10.55308848 10.49694659 6.267928775 15.25526237 13.66265902 10.88148303 6.685122492 11.39510869
12.01283007 9.060820296 8.742273354 7.931916479 11.69278534 10.03749599 10.70256143 8.818476992 8.256507365 10.90540289 11.27217358 7.529656884
11.83097061 8.217853913 11.26994807 12.78244535 8.869607339 11.87508891 11.95848799 9.270000217 8.711163529 9.147643674 9.997351719 11.32883683
10.89517599 7.466063637 11.44750761 14.73244987 9.548244139 11.13268559 9.786286782 7.360658104 8.39608648  9.01853547  13.14751703 8.895122216
9.670120389 12.9212866  12.66213806 7.606830997 7.120908791 10.43264777 6.678386624 10.92704464 9.43212972  10.19834234 7.21390979  8.066699553
8.277448369 9.981987293 10.12899305 7.344549757 6.959519054 10.31485    9.953131097 11.68982198 10.42556949 8.28508871  9.877206832 7.878172777

我有 12 列。我想为一个图中的每一列制作一个小提琴图。所以我使用了这个代码：

d %>%
  gather(col,val)%>%
  ggplot(aes(col,val)) +
  geom_violin()

其中 d 是我上面的数据框。生成绘图时，我得到的顺序为 V1,V10,V11,V12,V2,V3... 等等。我想始终保持与我的数据框中存在的顺序相同的顺序。我该怎么做？