R plotly中的离散颜色条

Question

我正在尝试用 R 绘制热图。 这是可重现的示例：

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，生成的图具有连续的比例。 我发现了这个StackOverflow question ，作者问了一个类似的问题。 我试图复制答案提供的解决方案，但我无法深入了解。 你能告诉我如何将比例设置为离散而不是连续颜色吗？

谢谢

EDIT1：添加了“a”变量定义

Answer 1

您需要按如下方式定义色标：

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))

Answer 2

Macro Sandris 的回答是完美的，并且很有魅力。

我只想补充一点，如果您需要两个以上的类，您可以使用以下示例：

2节课（见马科斯回答）

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

3班

colorScale <- data.frame(z=c(0,0.33,0.33,0.66,0.66,1),col=c("#440053","#440053","#FDE624","#FDE624","#DDE431","#DDE431"))

等等。 确保传入数据框的向量始终介于 0 到 1 之间。