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zhang
Asked: 2024-05-25 19:18:26 +0800 CST

如何在R中拆分data.table中的多个字段并相应地扩展行？[复制]

  • 772

我正在使用data.tableR 中的一个，其中多个字段可以包含多个用分号分隔的值。我试图将这些值分成单独的行，每个值对应于表中的一个新行。但挑战在于各个单独的领域是相关的，需要相应的拆分和扩展。

示例数据：

library(data.table)
df <- data.table(probe = c('A', 'B', 'C'), # there are many columns in real data
                 gene = c('geneA', 'geneB;geneC', 'geneD;geneH;geneI;geneO'), 
                 type = c('mRNA', 'mRNA;miRNA', 'mRNA;miRNA;mRNA;miRNA')) 

df
    probe                    gene                  type
1:      A                   geneA                  mRNA
2:      B             geneB;geneC            mRNA;miRNA
3:      C geneD;geneH;geneI;geneO mRNA;miRNA;mRNA;miRNA

预期输出：

df.new <- data.table(probe = c('A', 'B', 'B', 'C', 'C', 'C', 'C'), 
                     gene = c('geneA', 'geneB', 'geneC', 'geneD', 'geneH', 'geneI', 'geneO'), 
                     type = c('mRNA', 'mRNA', 'miRNA', 'mRNA', 'miRNA', 'mRNA', 'miRNA'))

df.new
    probe   gene   type
1:      A  geneA   mRNA
2:      B  geneB   mRNA
3:      B  geneC  miRNA
4:      C  geneD   mRNA
5:      C  geneH  miRNA
6:      C  geneI   mRNA
7:      C  geneO  miRNA

感谢您的好意建议

3 个回答

  1. Best Answer

    一种方法使用strsplit

    library(data.table)

df[, lapply(.SD[,c("gene", "type")], \(x) unlist(strsplit(x, ";"))), by = probe]
    probe   gene   type
   <char> <char> <char>
1:      A  geneA   mRNA
2:      B  geneB   mRNA
3:      B  geneC  miRNA
4:      C  geneD   mRNA
5:      C  geneH  miRNA
6:      C  geneI   mRNA
7:      C  geneO  miRNA
    • 2

  2. 您可以使用separate_longer_delim来自{tidyr}.

    library(tidyr)

separate_longer_delim(df, c(gene, type), ';')

#   probe  gene  type
# 1     A geneA  mRNA
# 2     B geneB  mRNA
# 3     B geneC miRNA
# 4     C geneD  mRNA
# 5     C geneH miRNA
# 6     C geneI  mRNA
# 7     C geneO miRNA
    • 1

  3. 使用splitstackshape包：

    splitstackshape::cSplit(df, c("gene", "type"), sep = ";", 
                        direction = "long", type.convert = FALSE)

#     probe   gene   type
#   <char> <char> <char>
#1:      A  geneA   mRNA
#2:      B  geneB   mRNA
#3:      B  geneC  miRNA
#4:      C  geneD   mRNA
#5:      C  geneH  miRNA
#6:      C  geneI   mRNA
#7:      C  geneO  miRNA
    • 0

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