是否可以在Code.org AppLab中检查NaN？

Question

我在Code.org AppLab上有个抛硬币模拟器。(为了清楚起见，它是在JavaScript中。)有一个文本输入框，用户可以在其中输入所需的翻转次数，然后单击它下面的按钮。我想让这段代码检查输入是否不是数字，所以我使用了isNaN...

onEvent("button2","click",function(){

if (getNumber("text_input1") == isNaN) {

    setText("text_area1","Please enter an integer.");
  } else {
    while ((flipCt < Math.abs(getNumber("text_input1")))) {
    flipVal = randomNumber(0, 1);
    flipCt++;
    if (flipVal == 1) {
        headcount++;
        headstreak++;
        if (headstreak > hscount) {
          hscount = headstreak;
        }
        tailstreak = 0;
      } else {
        tailcount++;
        tailstreak++;
        if (tailstreak > tscount) {
          tscount = tailstreak;
        }
        headstreak = 0;
      }
    }
    setText("VERY LONG LINE OF CODE, so I deleted it for this post."));
  }
});

所以..。第二行是我的问题。我似乎不能让它正确地检查NaN -如果我输入一个非数字的值，它总是跳到"else“部分，并将其设为0。有什么建议吗？

Answer 1

isNan的语法错误。您需要使用isNaN(getNumber("text_input1"))。如果是Nan，则返回true，否则返回false

Answer 2

您也可以尝试

onEvent("button2","click",function(){

if (!getNumber("text_input1").includes(1,2,3,4,5,6,7,8,9) { /// make sure to put the "!"

    setText("text_area1","Please enter an integer.");
  } else {
    while ((flipCt < Math.abs(getNumber("text_input1")))) {
    flipVal = randomNumber(0, 1);
    flipCt++;
    if (flipVal == 1) {
        headcount++;
        headstreak++;
        if (headstreak > hscount) {
          hscount = headstreak;
        }
        tailstreak = 0;
      } else {
        tailcount++;
        tailstreak++;
        if (tailstreak > tscount) {
          tscount = tailstreak;
        }
        headstreak = 0;
      }
    }
    setText("VERY LONG LINE OF CODE, so I deleted it for this post."));
  }
});

这将让它检查text_input1中是否没有任何数字。否则，它将运行您其余的代码。