自动修改复杂字符向量
自动修改复杂字符向量
提问于 2017-07-06 14:02:23
我有一个复杂的字符向量，向量的每个元素都由数字和字母组成。我想简化这个向量，以便将数字和/或字母的序列放到范围内。下面是一个例子，输入和输出向量应该是什么样的：
# Input vector
input_vec <- c("1,2,3,4,5", "1,2,3,5,6,7,8", "2,3,4,5", "A,B,C", "1,2,3,4,5,A,B,8,9,10,11")
# Here some function should be applied, to create the desired output vector automatically
# Desired output vector
output_vec <- c("1-5", "1-3,5-8", "2-5", "A-C", "1-5,A-B,8-11")我确信必须有一种方法来构建一个函数或使用一个包，以一种自动化的方式来完成这个任务，但不幸的是，我很难找到一个解决方案。任何帮助都是非常感谢的！
更新:添加了更复杂的向量
input_vec2 <- c("1,2,3,4,5", "1,2,3,5,6,7,8", "2,3,4,5", "A,B,C", "1,2,3,4,5,A,B,8,9,10,11",
"1", "1,2,3,-4", "lala,3") # This part is new
output_vec2 <- c("1-5", "1-3,5-8", "2-5", "A-C", "1-5,A-B,8-11",
"1", "1-3,-4", "lala,3") # This part is new回答 1
Stack Overflow用户
回答已采纳
发布于 2017-07-06 14:47:22
这可能还有点臃肿，但我尝试将问题分解为更小的函数。他们来了。首先，一些一般辅助函数
# Is value numeric?
is_numeric <- function(x) suppressWarnings(!is.na(as.numeric(x)))
# Greate IDs for sequences of values using run-length encoding
rleg <- function(x) {
r <- rle(x);
val <- list(group_value = r$values)
r$values <- seq_along(r$values);
val$group_id <- inverse.rle(r)
val
}现在有一些更具体的帮手来解决这个问题
collapse_sequence <- function(x) {
if (length(x)>1) {
paste0(x[1],"-", x[length(x)])
} else {
x
}
}
find_runs <- function(x, key=x) {
nona <- function(x) {x[is.na(x)]<-0; x}
run <- cumsum(nona(c(1,diff(key)))!=1)
Map(collapse_sequence, split(x, run))
}
collapse_numeric <- function(x) {
paste(sapply(find_runs(x, as.numeric(x)), collapse_sequence), collapse=",")
}
collapse_character <- function(x) {
key <- sapply(x, function(z) ifelse(nchar(z)==1, utf8ToInt(z), NA))
paste(sapply(find_runs(x, key), collapse_sequence), collapse=",")
}
collapse_runs <- Vectorize(function(x) {
x <- strsplit(x, ",")[[1]]
type <- ifelse(is_numeric(x), 1, ifelse(nchar(x)==1, 2, 3))
group <- rleg(type)
runs <- Map(function(v, type) {
if(type==1) {
collapse_numeric(v)
} else {
collapse_character(v)
}
},split(x, group$group_id), group$group_value)
paste(runs, collapse=",")
})最后，我们用您的输入测试它。
input_vec <- c("1,2,3,4,5", "1,2,3,5,6,7,8", "2,3,4,5", "A,B,C", "1,2,3,4,5,A,B,8,9,10,11")
unname(collapse_runs(input_vec))
# [1] "1-5" "1-3,5-8" "2-5" "A-C" "1-5,A-B,8-11"
input_vec2 <- c("1,2,3,4,5", "1,2,3,5,6,7,8", "2,3,4,5", "A,B,C", "1,2,3,4,5,A,B,8,9,10,11", "1",
"1,2,3,-4", "lala,3")
unname(collapse_runs(input_vec2))
# [1] "1-5" "1-3,5-8" "2-5" "A-C" "1-5,A-B,8-11"
# [6] "1" "1-3,-4" "lala,3"页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/44951131
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