R图中的离散颜色条

Question

我试图用R绘制一个热图.这是可重复的例子:

test <- structure(list(s1 = c(0L, 0L, 1L, 0L, 1L, 1L), s2 = c(1L, 1L, 
0L, 1L, 0L, 0L), s3 = c(0L, 0L, 0L, 0L, 0L, 0L), s4 = c(0L, 0L, 
0L, 0L, 0L, 0L), s5 = c(0L, 0L, 0L, 0L, 0L, 0L), s6 = c(0L, 0L, 
0L, 0L, 0L, 0L)), .Names = c("s1", "s2", "s3", "s4", "s5", "s6"
), row.names = c("5HT2 type receptor mediated signaling pathway", 
"5HT3 type receptor mediated signaling pathway", "5-Hydroxytryptamine degredation", 
"Alpha adrenergic receptor signaling pathway", "Alzheimer disease-amyloid secretase pathway", 
"Angiogenesis"), class = "data.frame")

以及用于生成热图的代码:

f1 <- list(
    family = "Arial, sans-serif",
    size = 5,
    color = "lightgrey")

f2 <- list(
    family = "Old Standard TT, serif",
    size = 10,
    color = "black")

a <- list(
  title = "",
  titlefont = f1,
  showticklabels = TRUE,
  tickangle = 45,
  tickfont = f2,
  exponentformat = "E")

plot_ly(z = as.matrix(test), 
        zmin=0, 
        zmax=1,
        x = colnames(test), 
        xgap = 2, 
        y = rownames(test), 
        ygap =2, 
        type = "heatmap", 
        colorbar=list(ypad = 30, tickmode="array", tickvals = c(0,1), color = 2, autocolorscale = F )) %>% 
  layout(xaxis = a,
         margin = list(l =500, r = 10, b = 200, t = 10))

如您所见,生成的图表具有连续的比例.我找到了这个StackOverflow问题,其中作者提出了类似的问题.我试图复制答案提供的解决方案,但我无法深究它.你能否告诉我如何将比例设置为离散而不是连续的颜色？

谢谢

EDIT1:添加了"a"变量定义

Answer 1

您需要定义颜色标度,如下所示:

colorScale <- data.frame(z=c(0,0.5,0.5,1),col=c("#440053","#440053","#FDE624","#FDE624"))
colorScale$col <- as.character(colorScale$col)

plot_ly(z = as.matrix(test), 
        x = colnames(test), 
        xgap = 2, 
        y = rownames(test), 
        ygap =2, 
        type = "heatmap", 
        colorscale=colorScale ,
        colorbar=list(ypad = 30, tickvals=c(0.25,0.75), ticktext=c(0,1))) %>% 
  layout(xaxis = a,
         margin = list(l =500, r = 10, b = 200, t = 10))