Question

我的JSON对象数组是：

#include <stdio.h>
#include <string.h>

int main()
{
   char string_buffer[21];
   int i, length;
   int flag = 0;

   print f("Input a string\n");
   scanf("%20s", string_buffer);

   length = strlen(string_buffer);

   for(i=0; i < length; i++) {
      if(string_buffer[i] != string_buffer[length-i-1]) {
         flag = 1;
         break;
      }
   }

   if(flag) {
      printf("%sNot a Palindrome.\n");
   }
   else {
      printf("%sPalindrome.\n");
   }
   return 0;
}

我想创建一个新的JSON对象数组，这些对象应该只包含上面数组[{ "stateCd": "IL", "value": "Illinois", "selected": "false" }, { "stateCd": "CA", "value": "California", "selected": "true" }, { "stateCd": "NY", "value": "New york", "selected": "false" }]的那些对象。

我试过selected:false：

concat

但是这会将angular.forEach($scope.oldJsonArr, function (value, index) { if($scope.oldJsonArr[index].selected=="false"){ $scope.newJsonArr.concat($scope.oldJsonArr[index]); } });作为未定义返回。任何帮助表示赞赏！

Answer 1

以下是代码：

$scope.oldJsonArr = [{"stateCd": "IL", "value": "Illinois", "selected": "false"}, {
        "stateCd": "CA",
        "value": "California",
        "selected": "true"
    }, {"stateCd": "NY", "value": "New york", "selected": "false"}];

    $scope.newJsonArr = [];

    angular.forEach($scope.oldJsonArr, function (value, index) {
        if ($scope.oldJsonArr[index].selected == "false") {
            $scope.newJsonArr.push($scope.oldJsonArr[index]);
        }
    });

    console.info($scope.newJsonArr);

您必须定义变量，否则它们将保持undefined
您必须使用.push()方法

Answer 2

您可以使用Array.prototype.filter（）方法。

var falseFilter = function(value) {
    return value.selected == "false";
};

var newJsonArray = oldJsonArray.filter(falseFilter);

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter

Answer 3

使用Filter中的JavaScript，而不是使用库实用程序功能。

var people = [
  { firstname:"Micro",  hasSocialNetworkSite: false, lastname:"Soft", site:"http://microsoft.com" },
  { firstname:"Face",   hasSocialNetworkSite: true, lastname:"Book", site:"http://facebook.com" },
  { firstname:"Go",     hasSocialNetworkSite: true, lastname:"ogle", site:"http://google.com" },
  { firstname:"Twit",   hasSocialNetworkSite: true, lastname:"Ter", site:"http://twitter.com" },
  { firstname:"App",    hasSocialNetworkSite: false, lastname:"Le",   site:"http://apple.com" },
  { firstname:"Master", hasSocialNetworkSite: false, lastname:"Card", site:"http://mastercard.com" }
];

var filteredResult = people.filter(function(v) {
  return v.hasSocialNetworkSite == true; // Filter out the appropriate one
});

document.write("Social Networking Site<br>");

for (var i in filteredResult) {
  document.write(filteredResult[i].site + "<br>")
}

参考资料详细了解：
  https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/filter
  https://msdn.microsoft.com/en-us/library/ff679973(v=vs.94).aspx
  http://www.w3schools.com/jsref/jsref_filter.asp

如何将现有json对象数组的某些对象复制到新的json数组

3 个答案: