[RUBY] How to use collection_select

This time, I will explain how to use collection_select.

Thing you want to do

I want to give an id to each element in the select and display it by name. Like this.

Image from Gyazo

How to use

collection_select has options, HTML attributes, etc., and you can change various appearances by changing them, but this time I will add an empty option "Please select" at the beginning, which is the most orthodox. I would like.

The model is like this.

= f.collection_select column name,Array of elements,Item of value attribute,Text item, { prompt: "Please select" } 

It looks like this when actually used.

= f.collection_select :prefecture, @prefecture, :id, :name, { prompt: "Please select" } 

#@Put all prefecture information in prefecture (instance variable)
#Since I want to give an id with the value of the element, the item part of the value attribute is:to id
#I want to display by name in the text, so the item part of the text is:to name

Image from Gyazo

Basically, collection_select is often used in parallel with active_hash. It may be more efficient to study active_hash and then cellection_select.

How to use for active_hash

https://qiita.com/Yu-8chan/items/9f19e2495937f4e36dde

Reference material

https://railsdoc.com/page/collection_select

that's all

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