我有一个dataframe作为R，如下所示，其中包括条件＆＃34;使用＆＃34;，＆＃34;认证二手＆＃34;和＆＃34;新。在我的实际数据集中，当我读入数据集时，此变量将作为chr加载。使用factor函数，我知道如何将chr转换为factor，但我想保持因子的顺序，并设置＆＃34;使用＆＃34;作为基线。
我尝试过所有可以找到的东西，但我显然遗漏了一些东西。如何正确将chr转换为有序因子并指定订单级别？
# example df
df <- data.frame(condition = c('Certified pre-owned', 'Used', 'Used', 'Used', 'Used', 'Used', 'New', 'Used', 'Used'))
# show structure
str(df)
'data.frame': 9 obs. of 1 variable:
$ condition: Factor w/ 3 levels "Certified pre-owned",..: 1 3 3 3 3 3 2 3 3
# change order of conditoin
df$condition <- as.ordered(df$condition, levels=c("Used", "Certified pre-owned", "New"))
Error in as.ordered(df$condition, levels = c("Used", "Certified pre-owned", : unused argument (levels = c("Used", "Certified pre-owned", "New"))
Traceback:
1. as.ordered(df$condition, levels = c("Used", "Certified pre-owned", "New"))
# convert to factor, but without levels
df$condition <- as.ordered(factor(df$condition))
# but the order puts them in alphabetical order, which is not what I want
levels(df$condition)
'Certified pre-owned' 'New' 'Used'