是否有可能在基数R替换多个整数与相应的字符串，如字典?

Question

类似于这个问题:替换r中的多个值，但是:我想只使用基数r并且我想替换整数，所以下面采用的命名向量解决方案不起作用:

testing <- data.frame(
var1 = c(1, 6, 17)
)
# this is not possible
dict <- c(
1 = 'ICMP', 
6 = 'TCP', 
17 = 'UDP', 
)
testing$var1 <- dict[testing$var1]

我知道我能做到

testing$var1[testing$var1 == 1] <- "ICMP"
testing$var1[testing$var1 == 6] <- "TCP"
testing$var1[testing$var1 == 17] <- "UDP"

但是以R为底没有更方便的方法吗?

Answer 1

# create named vector dict
dict <- c('ICMP', 'TCP', 'UDP')
names(dict) <- c(1,6,17)
# replace matching values
testing$var2 <- dict[as.character(testing$var1)]
#   var1 var2
# 1    1 ICMP
# 2    6  TCP
# 3   17  UDP

Answer 2

testing <- data.frame(
var1 = c(1, 6, 17)
)
dict <- data.frame(code = c(1, 6, 17), abbr = c('ICMP', 'TCP', 'UDP'))
merge(testing, dict, by.x = "var1", by.y = "code")
#  var1 abbr
#1    1 ICMP
#2    6  TCP
#3   17  UDP
testing$var1 <- merge(testing, dict, by.x = "var1", by.y = "code")$abbr

Answer 3

有很多选项。首先，您可以使用字符串作为索引:

dict <- c("1" = "ICMP", "6" = "TCP")
dict[ as.character(testing$var) ]

您可以通过执行names(dict) <- c(1, 6)来实现相同的目标。

然后，你可以使用反向哈希:

dict <- c(ICMP = 1, TCP = 6)
names(dict)[ match(testing$var1, dict) ]