r - 如何按照用户定义的顺序(例如非字母顺序)对数据框进行排序

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Custom sorting (non-alphabetical)

(4个答案)


5年前关闭。




给定数据框 dna

> dna
chrom   start
chr2    39482
chr1    203918
chr1    198282
chrX    7839028
chr17   3874

以下代码按 dna的字母升序和 $chrom的数字升序对 $start进行重新排序:

> dna <- dna[with(dna, order(chrom, start)), ]
> dna
chrom   start
chr1    198282
chr1    203918
chr17   3874
chr2    39482
chrX    7839028

但是，我希望能够按如下所示排序 $chrom(为此处示例简化):

chrom_order <- c("chr1","chr2", "chr17", "chrX")

我不允许将东西重命名，例如 chr1到 chr01。

最佳答案

您需要在levels中指定factor，然后将order与索引一起使用:

zz <- "chrom   start
chr2    39482
chr1    203918
chr1    198282
chrX    7839028
chr17   3874"
Data <- read.table(text=zz, header = TRUE)

library(Hmisc)
library(gdata)

Data$chrom  <- reorder.factor(Data$chrom , levels = c("chr1","chr2", "chr17", "chrX"))

Data[order(Data$chrom), ]
  chrom   start
2  chr1  203918
3  chr1  198282
1  chr2   39482
5 chr17    3874
4  chrX 7839028  

或者您可以使用以下方法:

> Data$chrom  <- factor(chrom , levels = c("chr1","chr2", "chr17", "chrX"))
> Data[order(Data$chrom), ]
  chrom   start
2  chr1  203918
3  chr1  198282
1  chr2   39482
5 chr17    3874
4  chrX 7839028

或使用此:

> Data$chrom <- reorder(Data$chrom, new.order=c("chr1","chr2", "chr17", "chrX"))
> Data[order(Data$chrom), ]

关于r - 如何按照用户定义的顺序(例如非字母顺序)对数据框进行排序，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/21549331/

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Answer 1

您需要在levels中指定factor，然后将order与索引一起使用:

zz <- "chrom   start
chr2    39482
chr1    203918
chr1    198282
chrX    7839028
chr17   3874"
Data <- read.table(text=zz, header = TRUE)

library(Hmisc)
library(gdata)

Data$chrom  <- reorder.factor(Data$chrom , levels = c("chr1","chr2", "chr17", "chrX"))

Data[order(Data$chrom), ]
  chrom   start
2  chr1  203918
3  chr1  198282
1  chr2   39482
5 chr17    3874
4  chrX 7839028  

或者您可以使用以下方法:

> Data$chrom  <- factor(chrom , levels = c("chr1","chr2", "chr17", "chrX"))
> Data[order(Data$chrom), ]
  chrom   start
2  chr1  203918
3  chr1  198282
1  chr2   39482
5 chr17    3874
4  chrX 7839028

或使用此:

> Data$chrom <- reorder(Data$chrom, new.order=c("chr1","chr2", "chr17", "chrX"))
> Data[order(Data$chrom), ]