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[英]How to sort a character vector where elements contain numbers and letters in R?
[英]How to sort a character vector where elements contain letters and numbers?
我有一個字符數組
cf <- c("V440","V457","V116","V327","V446","V108",
"V155","V217","V120","V51","V477")
我想按降序對它進行排序,這樣我就有一個像這樣的 output :
V51
V108
V116
V120
V155
V217
V327
V440
V446
V457
V477
我試過這樣的sort.list()
cf[sort.list(cf)]
並得到了這個答案:
[1] "V108" "V116" "V120" "V155" "V217" "V327" "V440" "V446" "V457" "V477" "V51"
並且還嘗試了order()
並得到了相同的結果。
有人能幫助我嗎
嘗試mixedsort
從“gtools”套餐:
> # install.packages("gtools") ## Uncomment if not already installed
> library(gtools)
> mixedsort(cf)
[1] "V51" "V108" "V116" "V120" "V155" "V217" "V327" "V440" "V446" "V457" "V477"
如果您不想使用mixedsort
(不知道為什么不使用),並且如果您的向量具有非常一致的模式(例如字母后跟數字),您也可以嘗試這樣的操作。 (注:相對未經測試。 )
newvec <- c("V440", "V457", "V116", "V327", "V446", "V108", "V155",
"V217", "V120", "V51", "V477", "B22", "A10", "Z01")
newvec[order(gsub("([A-Z]+)([0-9]+)", "\\1", newvec),
as.numeric(gsub("([A-Z]+)([0-9]+)", "\\2", newvec)))]
# [1] "A10" "B22" "V51" "V108" "V116" "V120" "V155" "V217" "V327" "V440"
# [11] "V446" "V457" "V477" "Z01"
這里有很多正確的答案,這是另一種方式,只是為了好玩。
cf[order(nchar(cf), cf)]
# [1] "V51" "V108" "V116" "V120" "V155" "V217" "V327" "V440" "V446" "V457" "V477"
使用str_sort
函數的一行代碼中的另一個解決方案(來自stringr
packg。)
# install.packages("stringr") ## Uncomment if not already installed
library(stringr)
str_sort(cf, numeric = TRUE)
[1] "V51" "V108" "V116" "V120" "V155" "V217" "V327" "V440" "V446" "V457" "V477"
只需刮掉前面的“V”字符即可構建排序向量。 不需要額外的花哨工具。
vals <- as.numeric(gsub("V","", cf))
cf[order(vals)]
[1] "V51" "V108" "V116" "V120" "V155" "V217" "V327" "V440" "V446"
[10] "V457" "V477"
R 正確地按字母順序排列字符串,這就是您得到該結果的原因。
除了@Ananda 非常好的答案,如果你想使用基數 R,你可以使用strsplit
從每個字符串中刪除“V”,然后使用as.numeric
將字符串轉換為整數:
vals <- as.numeric(sapply(cf, FUN=function(x){strsplit(x, "V")[[1]][2]}))
現在您可以使用vals
對字符串進行排序
cf[order(vals)]
這是一個使用names
和sort
的基本方法(Ananda 非常巧妙):
cf <- c("V440","V457","V116","V327","V446","V108",
"V155","V217","V120","V51","V477")
cf2 <- as.numeric(gsub("[^[:digit:]]", "", cf))
names(cf2) <- seq_along(cf2)
cf[as.numeric(names(sort(cf2)))]
## > cf[as.numeric(names(sort(cf2)))]
## [1] "V51" "V108" "V116" "V120" "V155" "V217" "V327"
## [8] "V440" "V446" "V457" "V477"
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