如何插入“；1“；在R中某列的起始位置？

我的数据（主数据）中有一列名为unit

master_data$unit <- c("Tonnes","1000 Tonnes","Numbers","1000 Numbers")

---

master_data$unit检查
unit
是否以数字开头。如果不是，请在开头粘贴
1

unit <- c("Tonnes","1000 Tonnes","Numbers","1000 Numbers")
ifelse(grepl("^\\d", unit), unit, paste("1", unit))
#[1] "1 Tonnes"     "1000 Tonnes"  "1 Numbers"    "1000 Numbers"

unit我们可以使用
sub
。这将匹配一个字符串，其中所有字符都是“字字符”，并替换为“1（匹配的字符）”：

单位
master_data$unit_len <- sapply(strsplit(master_data$unit, " "), length)


if (master_data$unit_len == 1) {
  paste("1 ", master_data$unit, sep="")
}

unit <- c("Tonnes","1000 Tonnes","Numbers","1000 Numbers")
ifelse(grepl("^\\d", unit), unit, paste("1", unit))
#[1] "1 Tonnes"     "1000 Tonnes"  "1 Numbers"    "1000 Numbers"

unit <- c("Tonnes","1000 Tonnes","Numbers","1000 Numbers")

sub('^(\\w+)$', '1 \\1', unit)
# [1] "1 Tonnes"     "1000 Tonnes"  "1 Numbers"    "1000 Numbers"