R:使用自定义顺序按名称重新排序数字向量 [英] R: Re-order numeric vector by name using custom order

问题描述

我有一个数字向量，想使用自定义顺序按名称重新排序.

I have a a numeric vector and want to re-order by name, using a custom order.

x <- sample(1:20, 5)
names(x) <- c("feb", "may", "mar", "jan", "apr")
x
feb may mar jan apr 
  7  10   5  13  11 

如您所见，向量不是按月顺序排列的

As you can see, the vectors are not in month order

我希望使用名称通过月份顺序重新排序这个字符向量，即 jan、feb、mar、apr、may...

I wish to re-order this character vector through month order using the names, i.e. jan, feb, mar, apr, may...

这怎么可能?

注意:我追求的是一种可以用于所有名称/字符串的方法，而不是专门用于日期对象

note: I am after a method that can be used on all names/character strings, rather than specifically date objects

推荐答案

我们可以将'x'的names转换为factor并设置levels 到小写的 month.abb，应用 order 并按该顺序获取 'x'.

We can convert the names of 'x' to factor and settting the levels to the month.abb in lowercase, apply the order and get the 'x' in that order.

x[order(factor(names(x), levels=tolower(month.abb)))]
jan feb mar apr may 
 13  7   5  11  10 

转换为 factor 并指定 levels 可以按自定义顺序应用于任何字符向量，否则，默认情况下，排序基于字母顺序，即

The conversion to factor with levels specified can be applied to any character vector in a custom order, otherwise, by default, the ordering is based on alphabetical order i.e.

x[order(names(x))]

假设，如果希望顺序为jan"、mar"、apr"、may"、feb"，请将其用作 factor 中的 levels 调用

Suppose, if want the order to be say, 'jan', 'mar', 'apr', 'may', 'feb', use that as levels in the factor call

x[order(factor(names(x), levels = c('jan', 'mar', 'apr', 'may', 'feb')))]

<小时>

因为 OP 在评论中以自定义顺序发布了另一个向量

---

As the OP posted another vector in a custom order in the comments

x1 <- c(icecream = 3, jelly = 4, fruit = 5)
x1[order(factor(names(x1), levels = c("jelly", "fruit", "icecream")))]
#   jelly    fruit icecream 
#      4        5        3 

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