如何從JavaScript中的JSON字符串讀取特定屬性？

Question

如何使用JavaScript從此字符串中讀取agent_code？請給我解釋一下邏輯。

JSON（單行）：

[{"name":"NYC","zone_id":"1","totalagents":"40","agents":[{"id":"1","agent_code":"====="},{"id":"2","agent_code":"====="},{"id":"3","agent_code":"Christian"},{"id":"4","agent_code":"Tom"},{"id":"5","agent_code":"Dave Damsky"},{"id":"6","agent_code":"====="},{"id":"7","agent_code":"Andrew"},{"id":"8","agent_code":"Paolo"},{"id":"9","agent_code":"Josh"},{"id":"10","agent_code":"Shipster Van"},{"id":"11","agent_code":"====="},{"id":"16","agent_code":"Christian2"},{"id":"20","agent_code":"Nathan"},{"id":"21","agent_code":"Aaron"},{"id":"22","agent_code":"Rob"},{"id":"23","agent_code":"Taylor"},{"id":"24","agent_code":"Drea"},{"id":"25","agent_code":"Mario "},{"id":"26","agent_code":"Julio"},{"id":"27","agent_code":"Abbas"},{"id":"28","agent_code":"Ahmed"},{"id":"29","agent_code":"David Damsky"},{"id":"30","agent_code":"Micheal"},{"id":"31","agent_code":"Moe"},{"id":"32","agent_code":"Luis"},{"id":"33","agent_code":"Darin"},{"id":"37","agent_code":"Alan"},{"id":"39","agent_code":"Cristian Marte"},{"id":"40","agent_code":"Cody"},{"id":"41","agent_code":"David Pinto"},{"id":"42","agent_code":"Will "},{"id":"44","agent_code":"Evan"},{"id":"45","agent_code":"Santiago"},{"id":"46","agent_code":"John"},{"id":"47","agent_code":"Moubeen"},{"id":"49","agent_code":"Devin Armstrong"},{"id":"50","agent_code":"Marco Bell"},{"id":"51","agent_code":"Youness Benzaid"},{"id":"52","agent_code":"Amin Mechouche"},{"id":"53","agent_code":"Franco Herrera"}]}]

JSON（格式化）：

[ 
    { 
     "name": "NYC", 
     "zone_id": "1", 
     "totalagents": "40", 
     "agents": [ 
      { 
       "id": "1", 
       "agent_code": "=====" 
      }, 
      { 
       "id": "2", 
       "agent_code": "=====" 
      }, 
      { 
       "id": "3", 
       "agent_code": "Christian" 
      }, 
      { 
       "id": "4", 
       "agent_code": "Tom" 
      }, 
      { 
       "id": "5", 
       "agent_code": "Dave Damsky" 
      }, 
      { 
       "id": "6", 
       "agent_code": "=====" 
      }, 
      { 
       "id": "7", 
       "agent_code": "Andrew" 
      }, 
      { 
       "id": "8", 
       "agent_code": "Paolo" 
      }, 
      { 
       "id": "9", 
       "agent_code": "Josh" 
      }, 
      { 
       "id": "10", 
       "agent_code": "Shipster Van" 
      }, 
      { 
       "id": "11", 
       "agent_code": "=====" 
      }, 
      { 
       "id": "16", 
       "agent_code": "Christian2" 
      }, 
      { 
       "id": "20", 
       "agent_code": "Nathan" 
      }, 
      { 
       "id": "21", 
       "agent_code": "Aaron" 
      }, 
      { 
       "id": "22", 
       "agent_code": "Rob" 
      }, 
      { 
       "id": "23", 
       "agent_code": "Taylor" 
      }, 
      { 
       "id": "24", 
       "agent_code": "Drea" 
      }, 
      { 
       "id": "25", 
       "agent_code": "Mario " 
      }, 
      { 
       "id": "26", 
       "agent_code": "Julio" 
      }, 
      { 
       "id": "27", 
       "agent_code": "Abbas" 
      }, 
      { 
       "id": "28", 
       "agent_code": "Ahmed" 
      }, 
      { 
       "id": "29", 
       "agent_code": "David Damsky" 
      }, 
      { 
       "id": "30", 
       "agent_code": "Micheal" 
      }, 
      { 
       "id": "31", 
       "agent_code": "Moe" 
      }, 
      { 
       "id": "32", 
       "agent_code": "Luis" 
      }, 
      { 
       "id": "33", 
       "agent_code": "Darin" 
      }, 
      { 
       "id": "37", 
       "agent_code": "Alan" 
      }, 
      { 
       "id": "39", 
       "agent_code": "Cristian Marte" 
      }, 
      { 
       "id": "40", 
       "agent_code": "Cody" 
      }, 
      { 
       "id": "41", 
       "agent_code": "David Pinto" 
      }, 
      { 
       "id": "42", 
       "agent_code": "Will " 
      }, 
      { 
       "id": "44", 
       "agent_code": "Evan" 
      }, 
      { 
       "id": "45", 
       "agent_code": "Santiago" 
      }, 
      { 
       "id": "46", 
       "agent_code": "John" 
      }, 
      { 
       "id": "47", 
       "agent_code": "Moubeen" 
      }, 
      { 
       "id": "49", 
       "agent_code": "Devin Armstrong" 
      }, 
      { 
       "id": "50", 
       "agent_code": "Marco Bell" 
      }, 
      { 
       "id": "51", 
       "agent_code": "Youness Benzaid" 
      }, 
      { 
       "id": "52", 
       "agent_code": "Amin Mechouche" 
      }, 
      { 
       "id": "53", 
       "agent_code": "Franco Herrera" 
      } 
     ] 
    } 
] 

Answer 1

比方說你的上面是一個JSON字符串

var jsonString = '[{"name":"NYC","zone_id":"1","totalagents":"40","agents":[{"id":"1","agent_code":"====="},{"id":"2","agent_code":"====="},{"id":"3","agent_code":"Christian"},{"id":"4","agent_code":"Tom"},{"id":"5","agent_code":"Dave Damsky"},{"id":"6","agent_code":"====="},{"id":"7","agent_code":"Andrew"},{"id":"8","agent_code":"Paolo"},{"id":"9","agent_code":"Josh"},{"id":"10","agent_code":"Shipster Van"},{"id":"11","agent_code":"====="},{"id":"16","agent_code":"Christian2"},{"id":"20","agent_code":"Nathan"},{"id":"21","agent_code":"Aaron"},{"id":"22","agent_code":"Rob"},{"id":"23","agent_code":"Taylor"},{"id":"24","agent_code":"Drea"},{"id":"25","agent_code":"Mario "},{"id":"26","agent_code":"Julio"},{"id":"27","agent_code":"Abbas"},{"id":"28","agent_code":"Ahmed"},{"id":"29","agent_code":"David Damsky"},{"id":"30","agent_code":"Micheal"},{"id":"31","agent_code":"Moe"},{"id":"32","agent_code":"Luis"},{"id":"33","agent_code":"Darin"},{"id":"37","agent_code":"Alan"},{"id":"39","agent_code":"Cristian Marte"},{"id":"40","agent_code":"Cody"},{"id":"41","agent_code":"David Pinto"},{"id":"42","agent_code":"Will "},{"id":"44","agent_code":"Evan"},{"id":"45","agent_code":"Santiago"},{"id":"46","agent_code":"John"},{"id":"47","agent_code":"Moubeen"},{"id":"49","agent_code":"Devin Armstrong"},{"id":"50","agent_code":"Marco Bell"},{"id":"51","agent_code":"Youness Benzaid"},{"id":"52","agent_code":"Amin Mechouche"},{"id":"53","agent_code":"Franco Herrera"}]}]'; 

var json = JSON.parse(jsonString); // parse string into json 

現在由於這個json是一個長度爲1的數組，要獲得所有的代理代碼，你將不得不這樣做。

for (var i = 0; i <json[0].agents.length; i++) { 
     console.log(json[0].agents[i].agent_code); 

}