Ruby-on-rails Rails 单行 if else 语句
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Rails single line if else statement
提问by Ossie
I'm trying to write a single line if else statement in a view.
我正在尝试在视图中编写一行 if else 语句。
<%= collection.name ? collection.name : @miniature.name %>
I want it to put collection.name if one exists, otherwise I want it to put @miniature.name
如果存在，我希望它放置 collection.name，否则我希望它放置 @miniature.name
回答by Marek Lipka
To make it even clearer, you can use logical ORand ActiveSupport'sObject#presence(to put collection.nameonly if it exists and isn't blank):
为了更清楚，您可以使用逻辑OR和ActiveSupport'sObject#presence（collection.name仅当它存在且不为空时才放置）：
<%= collection.name.presence || @miniature.name %>
If you want to display collection.nameif it's not nil, but it's blank (empty string or string containing only whitespace), it will be enough to have:
如果你想显示collection.nameif it not nil，但它是空白的（空字符串或只包含空格的字符串），它就足够了：
<%= collection.name || @miniature.name %>
回答by davegson
Check for the presence of collection.namefirst.
首先检查是否存在collection.name。
<%= collection.name.present? ? collection.name : @miniature.name %>
回答by Richard Peck
Couldn't you have
你不能有
<%= collection.name ||= @minature.name %>
To those who downvoted - Set Ruby variable if it is not already defined
对于那些投反对票的人 -如果尚未定义 Ruby 变量，则设置它
