I have below code in helper:
我在helper中有以下代码:
arr = ['one', 'two', 'three']
errors = content_tag :ul do
arr.map do |msg|
content_tag :li, msg
end.join.html_safe
end
It works fine, but in the first version I tried each instead of map and it didn't work. Could anyone explain me why? (each version generated just <ul>onetwothree</ul>)
它工作正常,但在第一个版本我尝试了每个而不是地图,它没有工作。谁能解释我为什么? (每个版本只生成
-
onetwothree
)
1 个解决方案
#1
3
This is because Array#each returns the receiver itself on which it was called.But Array#map returns a new array containing the values returned by the block.
这是因为Array#每个都返回调用它的接收器本身。但是,Array#map返回一个包含块返回的值的新数组。
arr = ['one', 'two', 'three']
arr.each {|i| i + 'weak' }.join(" ") # "one two three"
arr.map {|i| i + 'weak' }.join(" ") #"oneweak twoweak threeweak"
#1
3
This is because Array#each returns the receiver itself on which it was called.But Array#map returns a new array containing the values returned by the block.
这是因为Array#每个都返回调用它的接收器本身。但是,Array#map返回一个包含块返回的值的新数组。
arr = ['one', 'two', 'three']
arr.each {|i| i + 'weak' }.join(" ") # "one two three"
arr.map {|i| i + 'weak' }.join(" ") #"oneweak twoweak threeweak"