如何访问cl-json从JSON解码的对象? [英] How to access object decoded from JSON by cl-json?

问题描述

我正在尝试在Common Lisp中获取JSON导入.我想出了如何从JSON字符串中解码对象，但是我不知道如何访问返回的对象的属性.要解码一个字符串(并将结果存储在*** tempjson **中)，我这样做:

I am trying to get JSON import in Common Lisp. I figured out how to decode an object from a JSON string, but I don't know how to access the properties of the object that's returned. To decode a string (and store the result in ***tempjson**), I do this:

(defun test-json ()
 (with-input-from-string
   (s "{\"foo\": [1, 2, 3], \"bar\": true, \"baz\": \"!\"}")
    (defparameter *tempjson* (json:decode-json s))))

如何访问 * tempjson * 数据.例如，如何获取 foo 属性的值?

How can I access *tempjson* data. For example, how can I get the value of the foo property?

推荐答案

decode-json似乎返回一个关联列表(至少在这种情况下；请参见 assoc :

decode-json appears to return an association list (at least in this case; see documentation). You can access the values with the function assoc:

(defun test-json ()
  (with-input-from-string (s "{\"foo\": [1, 2, 3], \"bar\": true, \"baz\": \"!\"}")
    (let ((data (json:decode-json s)))
      (format t "~a~%" (rest (assoc :foo data))))))

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