Question

昨天我做了这个小功能，工作正常。今天早上我检查它，它不再工作了。我不明白为什么。

代码在第一次调用'var color = dataPHP [i] ['color_code']时给出了错误;'

TypeError：'undefined'不是对象（评估'dataPHP [i] ['color_code']'）全局代码

  var color_code_hold = [];
  for (ix = 0; ix <= 5; ++ix){
    for (i = 0; dataPHP.length; ++i) {
      var color = dataPHP[i]['color_code'];
      if(color === ix){
        // alert('found ix=='+ix+'color==='+color);
        color_code_hold[color_code_hold.length] = color;
        break;
      }
      if(dataPHP.length >= 20){
        var check_length = dataPHP.length-4;
      }else{
        var check_length = dataPHP.length;
      }
      if(i >= check_length){
        // omit ix
        // alert('broke'+ix);
        break;
      }
    }
  }

  var total_value = 0;
  for(i = 0; i < color_code_hold.length; ++i){
    var cur_color_h = color_code_hold[i];// held value
    // alert('cur_color_h val'+cur_color_h);
    if(cur_color_h === 0){
      total_value = total_value+25;
      // alert('added 0');
    }else
    if(cur_color_h === 1){
      total_value = total_value+25;
      // alert('added 1');
    }else 
    if(cur_color_h === 2){
      total_value = total_value+20;
      // alert('added 2');
    }else
    if(cur_color_h === 3){
      total_value = total_value+15;
      // alert('added 3');
    }else
    if(cur_color_h === 4){
      total_value = total_value+10;
      // alert('added 4');
    }else
    if(cur_color_h === 5){
      total_value = total_value+5;
      // alert('added 5');
    }
  }

  math_rand_num = Math.floor((Math.random() * total_value) + 1);

  color_code_hold.sort(function(a, b){return a-b});

  first_add_value = 0;
  for(i = 0; i < color_code_hold.length; ++i){
    var cur_color = color_code_hold[i];
    if(cur_color === 0){
      second_add_value = first_add_value + 25;
      if(math_rand_num <= second_add_value){
        var select_color = 0;
        break;
      }else{
        first_add_value = second_add_value;
      }
    }
    if(cur_color === 1){
      second_add_value = first_add_value + 25;
      if(math_rand_num <= second_add_value){
        var select_color = 1;
        break;
      }else{
        first_add_value = second_add_value;
      }
    }
    if(cur_color === 2){
      second_add_value = first_add_value + 20;
      if(math_rand_num <= second_add_value){
        var select_color = 2;
        break;
      }else{
        first_add_value = second_add_value;
      }
    }
    if(cur_color === 3){
      second_add_value = first_add_value + 15;
      if(math_rand_num <= second_add_value){
        var select_color = 3;
        break;
      }else{
        first_add_value = second_add_value;
      }
    }
    if(cur_color === 4){
      second_add_value = first_add_value + 10;
      if(math_rand_num <= second_add_value){
        var select_color = 4;
        break;
      }else{
        first_add_value = second_add_value;
      }
    }
    if(cur_color === 5){
      second_add_value = first_add_value + 5;
      if(math_rand_num <= second_add_value){
        var select_color = 5;
        break;
      }else{
        first_add_value = second_add_value;
      }
    }
  }

  for (i = 0; i < dataPHP.length; ++i) {
    var color = dataPHP[i]['color_code'];
    if(color === select_color){
      var key = i;
      break;
    }
  }

我输入了一小段代码来检查它，并且它在先前声明的行上出现了错误。

var i = 0;
var color = dataPHP[i]['color_code'];
alert(color);

我真的不知道为什么它不起作用。你能不把某些变量放在for循环中吗？它怎么可能在昨天工作并且今天神秘地破裂？

此外，这是一个小数组样本。

var dataPHP = [
{"deck_id":"1001","card_key":"1005","front_side":"s1","back_side":"s2","card_three":"s3","last_seen":0,"color_code":0,"last_study":0,"placement":1},
{"deck_id":"1001","card_key":"1004","front_side":"a2","back_side":"a1","card_three":"a3","last_seen":0,"color_code":5,"last_study":1414769400,"placement":2}];

Answer 1

假设首先定义dataPHP。我没有看到您的测试用例存在问题。虽然注意你的for循环在这种情况下有问题：

for (i = 0;  dataPHP.length; ++i) {

需要：

for (i = 0; i < dataPHP.length; ++i) {

i必须大于dataPHP.length，导致无限循环错误输出。

<强> Here is an example

在for循环中从javascript中选择值

1 个答案: