Question

我有一个数据集，其中包含字符变量，一些变量只是字符，但有些只有数字，我想用数字更改它们。如何使用基本功能？

User

Answer 1

这个怎么样？

test_data <- cbind(
  sapply(test_data[1:4], function(x) as.numeric(as.character(x))),
  test_data[5])

test_data
#        V1      V2      V3      V4      V5
# 1 -0.2372  0.5900  0.3196 -1.2442 ST 123E
# 2  0.5231  0.7619  0.5639  0.2814   LD 34
# 3  0.0390  1.7421 -0.2890 -0.9240 ST 123E
# 4  1.6180 -0.8037 -0.0822  0.9123 ST 123E
# 5 -1.0774  0.7327  0.1760 -0.4972 ST 123E

str(test_data)
# 'data.frame': 5 obs. of  5 variables:
#   $ V1: num  -0.237 0.523 0.039 1.618 -1.077
# $ V2: num  0.59 0.762 1.742 -0.804 0.733
# $ V3: num  0.3196 0.5639 -0.289 -0.0822 0.176
# $ V4: num  -1.244 0.281 -0.924 0.912 -0.497
# $ V5: Factor w/ 2 levels "LD 34","ST 123E": 2 1 2 2 2

Answer 2

test_data[,!sapply(test_data, function(x) all(grepl("[A-z]", x)))] <- lapply(test_data[,!sapply(test_data, function(x) all(grepl("[A-z]", as.character(x))))], as.numeric)

Answer 3

这也有效

myfun <- function(I) {
        if (any(grepl("[a-zA-Z]", I))) {  # does column contain characters?
            return(I)  # if yes, return column as factor
        } else {
            return(as.double(I))  # if no, return as double
        }
    }

df <- Reduce("data.frame", lapply(test_data, myfun))
colnames(df) <- c(LETTERS[1:5])

        # A       B       C       D       E
# 1 -0.2372  0.5900  0.3196 -1.2442 ST 123E
# 2  0.5231  0.7619  0.5639  0.2814   LD 34
# 3  0.0390  1.7421 -0.2890 -0.9240 ST 123E
# 4  1.6180 -0.8037 -0.0822  0.9123 ST 123E
# 5 -1.0774  0.7327  0.1760 -0.4972 ST 123E

str(df)
# 'data.frame':   5 obs. of  5 variables:
 # $ A: num  -0.237 0.523 0.039 1.618 -1.077
 # $ B: num  0.59 0.762 1.742 -0.804 0.733
 # $ C: num  0.3196 0.5639 -0.289 -0.0822 0.176
 # $ D: num  -1.244 0.281 -0.924 0.912 -0.497
 # $ E: Factor w/ 2 levels "LD 34","ST 123E": 2 1 2 2 2

如何更改R数据集中的变量类型

3 个答案: