如何从JSON字符串访问值? [英] How do I access a value from a JSON string?

问题描述

我有一个变量.当我执行puts var_name时，我得到了这个哈希值:

I have a variable. When I do puts var_name I get this hash:

"{\"numConnections\": 163}"

但是，当我尝试从值numConnections中获取该数字163时，它不起作用.这是我正在尝试的:

But when I try to get that number 163 from the value numConnections it isn't working. Here is what I am trying:

connections = temp_var["\"numConnections\""]
puts connections.inspect

或:

connections = temp_var["numConnections"]
puts connections.inspect

两者均无效.

有什么想法要从那里提取163吗?

Any idea how to extract that 163 from there?

推荐答案

如果您有JSON字符串，则需要先将其解析为哈希，然后才能使用它以类似于哈希的方式访问其键和值.请考虑以下IRB会话:

If you have a JSON string, you need to parse it into a hash before you can use it to access its keys and values in a hash-like way. Consider this IRB session:

1.9.3p194 :001 > require 'json'
 => true
1.9.3p194 :002 > temp_var = "{\"numConnections\": 163}"
 => "{"numConnections": 163}"
1.9.3p194 :003 > temp_var.class
 => String 
1.9.3p194 :004 > JSON.parse(temp_var)
 => {"numConnections"=>163}
1.9.3p194 :005 > JSON.parse(temp_var)['numConnections']
 => 163

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