R:中断 for 循环

Question

你能确认下一个break是否取消了内部for循环吗？

   for (out in 1:n_old){

     id_velho <- old_table_df$id[out]
      for (in in 1:n)
      {
       id_novo <- new_table_df$ID[in]
       if(id_velho==id_novo)
       {
        break
       }else 
       if(in == n)
       {
       sold_df <- rbind(sold_df,old_table_df[out,])
       }
      }
    }

Answer 1

嗯，你的代码是不可重现的，所以我们永远无法确定，但这就是 help('break') 所说的:

break breaks out of a for, while or repeat loop; control is transferred to the first statement outside the inner-most loop.

所以是的，break 只会中断当前循环。您还可以通过以下方式查看它的实际效果:

for (i in 1:10)
{
    for (j in 1:10)
    {
        for (k in 1:10)
        {
            cat(i," ",j," ",k,"\n")
            if (k ==5) break
        }   
    }
}