R Can'；t更改ggplot2中点的颜色

我有下面的代码来绘制数据帧的3列。然而，所有的分数都是黑色的。我使用了“缩放颜色”手册来更改颜色，但不知怎的，它不起作用。我在stackoverflow这里似乎找不到一个可以帮助我更改示例中颜色的示例

这里的数据是从正态分布中随机抽样的

mydata=structure(list(Date = structure(c(17897, 17928, 17956, 17987, 
18017, 18048, 18078, 18109, 18140, 18170, 18201, 18231, 18262, 
18293, 18322, 18353, 18383, 18414, 18444, 18475, 18506, 18536, 
18567, 18597, 18628), class = "Date"), Negative = c(1.4141655319494, 
0.110440295731216, 0.948934488581693, -0.568804345547736, 2.5941323681341, 
-0.576531358591976, 0.0140858233994362, 0.417047398821457, 0.40775203476754, 
0.503079405364353, 0.582216941693738, 0.975455038921685, -0.75748007565926, 
-0.539048486852119, -1.32108557845339, -0.400035171762721, -0.514455119348609, 
-0.79146585550848, -1.29152175059664, -0.273634452593897, 1.27896590482248, 
-0.890934146690136, 1.69274558530204, -0.734127056929873, 2.03500225033899
), Positive = c(1.84798162431695, 0.336194709031236, -0.526314555130721, 
0.81393016767847, -0.674494642779354, 0.184731290132162, -1.05736058062172, 
-0.345573102134991, 1.66908547557711, 0.503138994187551, -1.45156413365354, 
-0.895076143928229, 0.752972360857702, -0.0649264113813166, -0.658013257355579, 
1.53459462657491, 1.07927660930829, -1.84317544285875, 1.9101559956179, 
0.281284440284935, -0.6133530878859, -0.0763652672538888, -0.0258348893568873, 
-0.132452157433536, 0.0282861349456584), Difference = c(0.163472791572347, 
0.48786089417894, -0.0181001510344034, 0.375304681512042, 0.715078177047736, 
2.08789600472356, 1.37847127292588, -0.181862033213813, -1.50754342902749, 
1.07667606823766, -0.989732304751403, 1.58700348048779, -0.228722064253061, 
1.19257166422696, 0.270071146326714, -1.88992793350162, 0.191075967126705, 
-0.418194656239356, -0.62877062386575, -0.386001148941901, 0.86754032457249, 
-0.61017910973132, -0.483208138238712, 0.31682251000527, 0.587632627281817
)), row.names = c(NA, -25L), class = "data.frame")

mydata %>% tidyr::gather("id", "value", 2:4) %>% 
  ggplot(., aes(Date, value))+
  geom_point()+
    scale_color_manual(name="",labels = c("Negative","Positive","Difference"), 
    values =c("red","blue","black"))

---

正如markus所提到的，您需要更改的是

ggplot（，aes（日期、值、颜色=id））

，以便ggplot知道哪个列与颜色相关。

您忘记了将变量映射到颜色。