Ruby on Rails-处理未设置或不存在的变量

Question

I was wondering if there is a better way to check if a variable exists, currently I do this

if !params['attribute']['institution'].blank?

But if attribute doesn't exist then a error is thrown.

I saw .try() but couldn't see how it would work in this situation.

Also can anyone recommend a good ruby book or ruby web resource ?

Thanks

Alex

Answer 1

You can use present? or presence which was recently described by a blog post by Ola Bini.

Answer 2

if params['attribute'] && params['attribute']['institution']

不是最漂亮的，但是有效。

Answer 3

You can use if params['attribute'].has_key? 'institution' if params['attribute'].has_key? 'institution'