如何在R中循环数据？

# 遍历向量
vec <- c(1, 2, 3, 4, 5)
for (i in vec) {
  print(i)
}

# 遍历列表
list <- list(a = 1, b = 2, c = 3)
for (i in list) {
  print(i)
}

# 遍历矩阵
mat <- matrix(1:9, nrow = 3)
for (i in seq_len(nrow(mat))) {
  for (j in seq_len(ncol(mat))) {
    print(mat[i, j])
  }
}

# 循环打印数字，直到达到10
i <- 1
while (i <= 10) {
  print(i)
  i <- i + 1
}

# 循环读取用户输入，直到输入quit为止
input <- ""
while (input != "quit") {
  input <- readline("请输入内容：")
  print(input)
}

# 使用apply对矩阵的每一行进行求和
mat <- matrix(1:9, nrow = 3)
row_sums <- apply(mat, 1, sum)
print(row_sums)

# 使用lapply对列表中的每个元素进行平方
list <- list(a = 1:3, b = 4:6, c = 7:9)
squared_list <- lapply(list, function(x) x^2)
print(squared_list)