Data which user saved make the initial value of checkbox [duplicate] - ruby

Question

This question already has answers here:
How to make a check_box checked in rails?
(11 answers)
Closed 2 years ago.
Background
In my app, users can choose multiple languages which they're able to speak on their profile edit page (users/edit.html.erb) from checkbox. Many-to-many relation is already written, so multiple data can be saved properly.
Now, when users came back to their profle edit page, all the checkbox are displayed in a blank. I would like to display languages with "checked" which user chose and saved.
users/edit.html.erb
<li>
<div class="col-1">Spoken languages:</div>
<div class="col-2">
<label><input type="checkbox" name="language[]" value="1">Japanese</label>
<label><input type="checkbox" name="language[]" value="2">English</label>
<label><input type="checkbox" name="language[]" value="3">Chinese</label>
<label><input type="checkbox" name="language[]" value="4">Spanish</label>
</div>
</li>
What I tried to do
I searched this kind of function, but I only found how to make a specific initial value (such as always check "English"). I would be grateful if someone give me advice.
Version
ruby 2.6.4p104
RubyGems 3.0.3
Rails 5.2.3

Answer 1

I was able to figure it out with include method. Thank you very much.
<label><input type="checkbox" name="language[]" value="1" <%= "checked='checked'" if #user.language_ids.include?(1) %>>Japanese</label>
<label><input type="checkbox" name="language[]" value="2" <%= "checked='checked'" if #user.language_ids.include?(2) %>>English</label>
<label><input type="checkbox" name="language[]" value="3" <%= "checked='checked'" if #user.language_ids.include?(3) %>>Chinese</label>
<label><input type="checkbox" name="language[]" value="4" <%= "checked='checked'" if #user.language_ids.include?(4) %>>Spanish</label>