等效于 .try() 用于哈希以避免“未定义的方法"；零错误?

问题描述

在 Rails 中，如果值不存在，我们可以执行以下操作以避免错误:

In Rails we can do the following in case a value doesn't exist to avoid an error:

@myvar = @comment.try(:body)

当我深入研究散列并且不想得到错误时，等价物是什么?

What is the equivalent when I'm digging deep into a hash and don't want to get an error?

@myvar = session[:comments][@comment.id]["temp_value"] 
# [:comments] may or may not exist here

在上述情况下，session[:comments]try[@comment.id] 不起作用.会怎样?

In the above case, session[:comments]try[@comment.id] doesn't work. What would?

推荐答案

你忘记在 try 之前放一个 .:

You forgot to put a . before the try:

@myvar = session[:comments].try(:[], @comment.id)

因为 [] 是您执行 [@comment.id] 时的方法名称.

since [] is the name of the method when you do [@comment.id].

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