ruby 问题总结

1.routes collection 和member的区别

例：

resources :photos do member do get :preview endend

resources :photos do collection do get :preview endend

结果

member /photos/1/preview preview_photo_path(photo)Acts on a specific resource so required id (preview specific photo)


collection /photos/preview preview_photos_url Acts on collection of resources(display all photos)

2.require 和 load的区别

require 只加载一次，load加载多次，load每次加载到该文件的时候执行改文件，require只在第一次执行是载入，以后碰到时自动忽略。require如果为ruby代码，可以省略后缀 。require将所有加载的文件保存在$变量中。

require ，load用于包含文件，include则用于包含的模块。

require一般用于加载库文件，load一般用于加载配置文件

3.join和spilt

join array to string

arr = ["hello", "world", 123]
puts arr.join(", ")
puts arr.join

hello, world, 123
helloworld123

spilt string to array

" now's  the time".split        #=> ["now's", "the", "time"]
" now's  the time".split('')   #=> ["now's", "the", "time"]
" now's  the time".split(//)   #=> ["", "now's", "", "the", "time"]
"1, 2.34,56, 7".split(%r{,\s*}) #=> ["1", "2.34", "56", "7"]
"hello".split(//)               #=> ["h", "e", "l", "l", "o"]
"hello".split(//, 3)            #=> ["h", "e", "llo"]
"hi mom".split(%r{\s*})         #=> ["h", "i", "m", "o", "m"]

"mellow yellow".split("ello")   #=> ["m", "w y", "w"]
"1,2,,3,4,,".split(',')         #=> ["1", "2", "", "3", "4"]