如何在JavaScript中创建一个变量条件作为参数？

我想测试一下轮盘赌游戏中有多少红色/黑色/偶数/奇数出现。如何在JavaScript中创建一个变量条件作为参数？

以下函数将遍历一个旋转列表n，并给出红色赢得和丢失的行数。同样的功能，可用于所有其他类型的连胜不过检查结果是不同的

color[n[i]] == "red"

我想通过一个不同的检查到这个函数测试找齐

n[i]%2 == 0

这可做了什么？

function test(n) 
{ 
    var wins = parseInt(0); 
    var losses = parseInt(0); 

    for(var i=0;i<n.length;i++) 
    { 
     if(color[n[i]] == "red") 
     { 
      wins += 1 
      losses = 0 
     } 
     else 
     { 
      wins = 0 
      losses += 1 
     } 

    } 
. 
. 
.

PART 2

这是完整代码。如果您点击'输入旋转'按钮和'切换数字键盘'按钮，然后添加数字8两次，然后显示3个警报。

我似乎无法得到3条消息显示在单独的行。我尝试了一些示例，但它总是在最后一条消息之前添加行返回。你知道如何在单独的行上获取多条消息吗？

<html> 
<head> 
<style> 
.bntcal { 
    padding: 10px 10px 10px 10px; 
    margin: 10px; 
} 
.bntcaladd { 
    padding: 10px 10px 10px 10px; 
    margin: 10px; 
} 

.bntshow{ 
    padding: 5px 5px 5px 5px; 
    margin: 5px; 
    width: 10%; 
} 
.spanhide { 
    display: none; 
} 
.bell { 
    float:left; 
    display: none; 
} 

</style> 
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script> 
<script> 
var wheel0 = [37,32,15,19,4,21,2,25,17,34,6,27,13,36,11,30,8,23,10,5,24,16,33,1,20,14,31,9,22,18,29,7,28,12,35,3,26]; 
var wheel00 = [37,28,9,26,30,11,7,20,32,17,5,22,34,15,3,24,36,13,1,38,27,10,25,29,12,8,19,31,18,6,21,33,16,4,23,35,14,2]; 
var wheel = wheel00; 
var wColor = ""; 
var numbers = []; 
var color = []; 



$(document).ready(function(){ 

    // --- Menu Buttons 
    $("#enterSpins").click(function(){ 
     $("#divSpins").show(); 
     $("#divAlerts").hide(); 
     $("#divHowTo").hide(); 
    }); 

    $("#setAlert").click(function(){ 
     $("#divAlerts").show(); 
     $("#divSpins").hide(); 
     $("#divHowTo").hide(); 
    }); 

    $("#howTo").click(function(){ 
     $("#divHowTo").show(); 
     $("#divSpins").hide(); 
     $("#divAlerts").hide(); 

    }); 

    // ---- Sub Buttons 
    $("#enterPad").click(function(){ 
     $("#showSpinsPad").toggle(); 
     $("#clearBox").toggle(); 
     $("#clearBox1").toggle(); 
     if(!$("#showSpinsPad").is(":hidden")) 
     { 
      $("#spins").prop("disabled", true) 
     } 
     else 
     { 
      $("#spins").prop("disabled", false) 
     } 

    }); 

    $(".bntcal").click(function(){ 
     $("#currentSpin").text($("#currentSpin").text()+$(this).val()) 
     if ($("#currentSpin").text().length > 2) 
     { 
      $("#currentSpin").text($(this).val()) 
     }  
    }); 


    $("#clear").click(function(){ 
     $("#currentSpin").text("") 
    }); 

    $("#add").click(function(){ 

     getWheel() 
     currentSpin = $("#currentSpin").text() 
     if(currentSpin.length > 0) 
     { 
      if ($("#spins").val().length > 0) 
      { 
       $("#spins").val($("#spins").val() + ", "); 
      } 
      if(parseInt(currentSpin)<37) 
      { 
       $("#spins").val($("#spins").val() + currentSpin); 
      } 
      if(parseInt(currentSpin) == 37) 
      { 
       $("#spins").val($("#spins").val() + "0"); 
      } 
      if(parseInt(currentSpin) == 38) 
      { 
       $("#spins").val($("#spins").val() + "00"); 
      } 
      if(parseInt(currentSpin)>38) 
      { 
       $("#spins").val($("#spins").val() + "0"); 
      } 

      $("#currentSpin").text("") 
     } 

     var n = GetUserNumbers(); 
     run(n) 
    }); 

    $("#undo").click(function(){ 
     var n = GetUserNumbers(); 

     if (n.length>0) 
     { 
      n.pop(); 
     } 
     $("#spins").val(n) 
     run(n) 
    }); 

    $("#clean").click(function(){ 
     $("#spins").val("") 
    }); 

    $("#run").click(function(){ 
     var n = GetUserNumbers(); 
     run(n) 
    }); 

}); 
// --------------------------------------------------------------- 
// --------------------- FUNCTIONS ------------------------------- 
// --------------------------------------------------------------- 

function run(n) 
{ 

    $("#alert").text("") 

    // Evens 
    var conditions = ['color[n] == "red"','color[n] == "black"','n%2 == 0 && n<37','n%2 == 1 && n<37','n > 18 && n<37','n < 19 && n>0'] 
    var checklocation = ['Red','Black','Even','Odd','High','Low'] 
    var idWins = "#evenwin" 
    var idLosses = "#evenloss" 

    checkCondition(n, conditions, checklocation, idWins, idLosses) 

    // Dozens 
    var conditions = ['n%3 == 1','n%3 == 2','n%3 == 0','n>=1 && n<=12','n>=13 && n<=24','n>=25 && n<=36'] 
    var checklocation = ['Row 1 [1,2,3..]','Row 2 [2,3,4..]','Row 2 [3,6,9..]','Dozen 1 [1-12]','Dozen 1 [13-24]','Dozen 1 [25-36]'] 
    var idWins = "#dozenwin" 
    var idLosses = "#dozenloss" 

    checkCondition(n, conditions, checklocation, idWins, idLosses) 
} 

function checkCondition(n, conditions, checklocation, idWins, idLosses) 
{ 
    for(var i=0; i<conditions.length; i++) 
    { 
     var check = function(n){ if(conditions[i]){ return true; } else { return false; }} 
     var wins = checkWins(n, check) 
     var losses = checkLosses(n, check) 
     if(wins >= $(idWins).val()) { $("#alert").text($("#alert").text()+" "+checklocation[i]+" loses "+wins+" times in a rows.<br/>")} 
     if(losses >= $(idLosses).val()) { $("#alert").text($("#alert").text()+" "+checklocation[i]+" loses "+losses+" times in a rows.<br/>")} 
    } 
} 

function checkWins(n, condition) 
{ 
    var wins = parseInt(0); 
    for(var i=0;i<n.length;i++) 
    { 
     if(condition(n[i])) 
     { 
      wins += 1 
     } 
     else 
     { 
      wins = 0 
     } 
    } 

    return wins 
} 

function checkLosses(n, condition) 
{ 
    var losses = parseInt(0); 
    for(var i=0;i<n.length;i++) 
    { 
     if(condition(n[i])) 
     { 
      losses = 0 
     } 
     else 
     { 
      losses += 1 
     } 
    } 
    return losses 
} 

$.fn.multiline = function(text){ 
    this.text(text); 
    this.html(this.html().replace(/\n/g,'<br/>')); 
    return this; 
} 


function getWheel() 
{ 
    if($("input[name=wheel]:checked").val()=="0") 
    { 
     wheel = wheel0 
    } 
    else 
    { 
     wheel = wheel00 
    } 
    color = GetColor(wheel) 
} 

function reset() 
{ 
    evenwins = parseInt(0); 
} 
function GetUserNumbers() 
{ 
    var n = $("#spins").val().split(","); 

    for(var x=0; x<n.length; x++) 
    { 
     if(n[x].trim() == "0") 
     { 
      n[x] = "37"; 
     } 
     if(n[x].trim() == "00") 
     { 
      n[x] = "38"; 
     } 
     n[x] = parseInt(n[x].trim()); 
    } 
    return n; 
} 

function GetColor(wheel) 
{ 
    var color = Array(); 
    if(wheel.length==37) 
    { 
     color[1] = "red"; 
     color[2] = "black"; 
     color[3] = "red"; 
     color[4] = "black"; 
     color[5] = "red"; 
     color[6] = "black"; 
     color[7] = "red"; 
     color[8] = "black"; 
     color[9] = "red"; 
     color[10] = "black"; 
     color[11] = "black"; 
     color[12] = "red"; 
     color[13] = "black"; 
     color[14] = "red"; 
     color[15] = "black"; 
     color[16] = "red"; 
     color[17] = "black"; 
     color[18] = "red"; 
     color[19] = "red"; 
     color[20] = "black"; 
     color[21] = "red"; 
     color[22] = "black"; 
     color[23] = "red"; 
     color[24] = "black"; 
     color[25] = "red"; 
     color[26] = "black"; 
     color[27] = "red"; 
     color[28] = "black"; 
     color[29] = "black"; 
     color[30] = "red"; 
     color[31] = "black"; 
     color[32] = "red"; 
     color[33] = "black"; 
     color[34] = "red"; 
     color[35] = "black"; 
     color[36] = "red"; 
     color[37] = "green"; 
    } 
    if(wheel.length==38) 
    { 
     color[1] = "red"; 
     color[2] = "black"; 
     color[3] = "red"; 
     color[4] = "black"; 
     color[5] = "red"; 
     color[6] = "black"; 
     color[7] = "red"; 
     color[8] = "black"; 
     color[9] = "red"; 
     color[10] = "black"; 
     color[11] = "black"; 
     color[12] = "red"; 
     color[13] = "black"; 
     color[14] = "red"; 
     color[15] = "black"; 
     color[16] = "red"; 
     color[17] = "black"; 
     color[18] = "red"; 
     color[19] = "red"; 
     color[20] = "black"; 
     color[21] = "red"; 
     color[22] = "black"; 
     color[23] = "red"; 
     color[24] = "black"; 
     color[25] = "red"; 
     color[26] = "black"; 
     color[27] = "red"; 
     color[28] = "black"; 
     color[29] = "black"; 
     color[30] = "red"; 
     color[31] = "black"; 
     color[32] = "red"; 
     color[33] = "black"; 
     color[34] = "red"; 
     color[35] = "black"; 
     color[36] = "red"; 
     color[37] = "green"; 
     color[38] = "green"; 
    } 
    return color; 
} 

</script> 
</head> 
<body> 
Toggle Displays</br><br/> 
<div > 
<button class="bntshow" id="enterSpins">Enter Spins</button><br/> 
<button class="bntshow" id="setAlert">Set Alerts</button><br/> 
<button class="bntshow" id="howTo">How To</button><br/> 
<input type="radio" name="wheel" value="0">0 Wheel<br/> 
<input type="radio" name="wheel" value="00" checked>00 Wheel<br/> 
</div><br/> 
<div id="alert"></div> 
<hr> 


<!-- Enter Spins --> 
<span class="spanhide" id="divSpins"> 
<button class="bntcaladd" id="enterPad">Toggle Numberpad</button><br/> 
<br/> 

<span class="spanhide" id='showSpinsPad'> 
<br/> 
<button class="bntcal" id="calculator" value="0">0</button> 
<button class="bntcal" id="calculator" value="00">00</button><br/> 
<button class="bntcal" id="calculator" value="1">1</button> 
<button class="bntcal" id="calculator" value="2">2</button> 
<button class="bntcal" id="calculator" value="3">3</button><br/> 
<button class="bntcal" id="calculator" value="4">4</button> 
<button class="bntcal" id="calculator" value="5">5</button> 
<button class="bntcal" id="calculator" value="6">6</button><br/> 
<button class="bntcal" id="calculator" value="7">7</button> 
<button class="bntcal" id="calculator" value="8">8</button> 
<button class="bntcal" id="calculator" value="9">9</button><br/> 
<button class="bntcaladd" id="clear">Clear</button> 
<button class="bntcaladd" id="add">ADD</button><span id="currentSpin"></span> 
<br/> 
<button class="bntcaladd" id="undo">Undo</button><br/> 
<span id="currentSpin"></span> 
<br/> 
</span> 
<span id="clearBox">Enter roulette numbers separated by a comma</span><br/> 
<textarea rows="10" cols="50" id="spins"></textarea><br/><br/> 
<span id="clearBox1"> 
<button id="clean">Clear Box</button> 
<button id="run">Run</button> 
</span> 

</span> 

<!-- Set Alerts --> 
<span class="spanhide" id="divAlerts"> 
<h2>Evens</h2> 
<input type="text" id="evenwin" value="2"> Wins in a row<br> 
<input type="text" id="evenloss" value="6"> Losses in a row<br> 
<br><br> 
<h2>Dozens</h2> 
<input type="text" id="dozenwin" value="6"> Wins in a row<br> 
<input type="text" id="dozenloss" value="6"> Losses in a row<br> 
<br><br> 

</span> 

<!-- How To --> 
<span class="spanhide" id="divHowTo"> 
How To 
</span> 


</body> 
</html>

来源

2016-08-17 user1854438

将'test'函数重写为'function test（n，callback）{...}'其中'callback'将返回true/false来表示优胜者/宽松。 –

是的，绝对！

在JavaScript中，您可以将函数保存到变量中，并将它们作为参数传递;这是JavaScript中最强大的方面之一。因此，举例来说，如果你要检查，如果颜色是红色，你可以写一个返回true的条件测试功能/假如下：

var checkColor = function(nElement){ 
     var color = color(nElement); 
     if(color == 'red'){ 
      return true; 
     } 
     else if(color == 'black'){ 
      return false; 
     } 
}

所以，现在，你有一个变量checkColor这是一个函数，检查一个颜色是否是红色的。现在，你可以通过这个功能到您的test功能是这样的：

function test(n,testFunc) 
{ 
var wins = parseInt(0); 
var losses = parseInt(0); 

for(var i=0;i<n.length;i++) 
{ 
    if(testFunc(n[i])) //testFunc = checkColor in this case since we passed in checkColor 
    { 
     wins += 1 
     losses = 0 
    } 
    else 
    { 
     wins = 0 
     losses += 1 
    } 

} 

test(n,checkColor); //This is where you pass in checkColor as your test func

因此例如，如果我们想要增加另一个测试甚至，我们可以写一个函数像这样：

var checkEven = function(nElement){ 
    if(nElement % 2 == 0){ 
      return true; 
    } 
    else{ 
      return false; 
    } 
}

而且使用这种新的情况类似，我们可以简单地运行test：

test(n,checkEven);

从这里所以，你应该了解如何创建测试功能并将其传递到通用测试功能。如果你需要澄清，不要犹豫，问！

来源

2016-08-17 20:21:51 Ted

这是心灵弯曲，但它很好。谢谢。我有另一个问题涉及到同样的事情。我应该问一个新的线程吗？ – user1854438

如果有新代码，那么是的。如果这只是一个概念性问题，你可以在这里问。但是，这完全取决于你 - 我认为这不重要;） – Ted

你能帮我解决另一个奇怪的问题吗？我可以通过电子邮件向你发送我的完整代码 – user1854438

如何在JavaScript中创建一个变量条件作为参数？

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