r - 如何将因子转换为数字

Question

我的数据:

data <- read.table(text = "Component    Method  Average StdErr
N170    Image   0,58904 0,0066948
P300    Image   0,84932 0,0048678
Sham    Image   0,23944 0,0058078
N170    Topo    0,64384 0,0065159
P300    Topo    0,90278 0,0040316
Sham    Topo    0,32877 0,0063921
N170    Joint   0,65278 0,0064788
P300    Joint   0,84722 0,0048959
Sham    Joint   0,26230 0,0059937", header = TRUE)

我想使用 ggplot2 绘制它。尝试计算误差线时，出现错误。我发现这是因为“平均”在这里是一个因素而不是数字。运行我的代码:

ggplot(data=data, aes(x=Method, y=Average, group=Component)) + 
  geom_line(aes(colour=Component), size=1)+
  geom_pointrange(aes(ymin=Average-StdErr, ymax=Average+StdErr))+
  geom_point(aes(colour=Component), size=3)+
  theme_classic()

给我这个错误信息:

Warning messages:
1: In Ops.factor(Average, StdErr) : ‘-’ not meaningful for factors
2: In Ops.factor(Average, StdErr) : ‘+’ not meaningful for factors
3: Removed 9 rows containing missing values (geom_pointrange).

我曾尝试使用此代码将 Average 和 StdErr 转换为数字，但它没有解决我的问题。

data$Average <- as.numeric(data$Average)
data$StdErr <- as.numeric(as.vector(data$StdErr))

或者，我尝试以 .csv 格式读取我的数据:

data <- read.csv(file="C:/Users/XXX/Desktop/XXX/XX/ggplot/corrComp_agg.csv", 
                 header=TRUE, sep=",")

但是收到一条错误消息说:

Error in read.table(file = file, header = header, sep = sep, quote = quote,  : 
  more columns than column names

我错过了什么？

Answer 1

您应该将逗号读作十进制字符.. 使用 dec = ","在 read.table陈述

data <- read.table(text = "Component    Method  Average StdErr
N170    Image   0,58904 0,0066948
                   P300    Image   0,84932 0,0048678
                   Sham    Image   0,23944 0,0058078
                   N170    Topo    0,64384 0,0065159
                   P300    Topo    0,90278 0,0040316
                   Sham    Topo    0,32877 0,0063921
                   N170    Joint   0,65278 0,0064788
                   P300    Joint   0,84722 0,0048959
                   Sham    Joint   0,26230 0,0059937", dec =",", header = TRUE)

现在您的 Average和 StdErr是数字

sapply(data, class)
#Component    Method   Average    StdErr 
# "factor"  "factor" "numeric" "numeric" 

所以，现在绘图很容易

ggplot(data=data, aes(x=Method, y=Average, group=Component)) + 
  geom_line(aes(colour=Component), size=1)+
  geom_pointrange(aes(ymin=Average-StdErr, ymax=Average+StdErr))+
  geom_point(aes(colour=Component), size=3)+
  theme_classic()