Question

对不起基本问题，但我无法弄清楚如何更改字符串和数字。我有一个数据框数据文件，列主题有28个不同的数字/主题（4,5,8,9,10,11,12等）。我需要将这些数字更改为字符串，例如＆＃39; sbj04＆＃39;，＆＃39; sbj05＆＃39;，＆＃39; sbj08＆＃39;，＆＃39; sbj09＆＃39;＆＃39; sbj10＆＃39;，＆＃39; sbj11＆＃39;，＆＃39; sbj12＆＃39;等我尝试了不同的东西，但他们没有工作。

datafile$subject = as.factor(datafile$subject) #it works
datafile$subject <- sub("^", "sbj", datafile$subject ) #it works, but all numbers become 'sbj4', 'sbj5', 'sbj8', 'sbj9', sbj10', etc.

以下代码无法返回我需要的内容

datafile[datafile$subject == "sbj4"] <- "sbj04"
datafile[datafile$subject == "sbj5"] <- "sbj05"
datafile[datafile$subject == "sbj8"] <- "sbj08"
datafile[datafile$subject == "sbj9"] <- "sbj09"

以下代码无法返回我需要的内容

datafile[datafile$subject == "sbj4",] <- datafile[datafile$subject == "sbj04",]
datafile[datafile$subject == "sbj5",] <- datafile[datafile$subject == "sbj05",]
datafile[datafile$subject == "sbj8",] <- datafile[datafile$subject == "sbj08",]
datafile[datafile$subject == "sbj9",] <- datafile[datafile$subject == "sbj09",]

以下代码无法返回我需要的内容

if (datafile$subject < 10) {
      datafile$subject <- sub("^", "sbj0", datafile$subject )
    } else{
      datafile$subject <- sub("^", "sbj", datafile$subject )
    }

Answer 1

如果您实际拥有数值，一种简单的方法是使用sprintf（在基数R中）。

示例：

> x <- 1:15
> sprintf("sbj%02.f", x)
 [1] "sbj01" "sbj02" "sbj03" "sbj04" "sbj05" "sbj06" "sbj07" "sbj08" "sbj09"
[10] "sbj10" "sbj11" "sbj12" "sbj13" "sbj14" "sbj15"

因此，你应该尝试类似的东西：

datafile$subject <- sprintf("sbj%02.f", datafile$subject)

将前导零添加到整数列

1 个答案: