What is the difference between <%, <%=, <%# and -%> in ERB in Rails?
http://stackoverflow.com/questions/998979/difference-between-and-in-rails/25617607#25617607
http://stackoverflow.com/questions/7996695/what-is-the-difference-between-and-in-erb-in-rails
<% %>
Executes the ruby code within the brackets.
<%= %>
Prints something into erb file.
<% -%>
Avoids line break after expression.
<%# %>
Comments out code within brackets; not sent to client (as opposed to HTML comments).
In Ruby 2.1 (not necessarily with Rails), the -
removes one trailing newline:
- the newline must be the first char after the
>
- no spaces are removed
- only a single newline is removed
- you must pass the
'-'
option to use it
Examples:
require 'erb'
ERB.new("<%= 'a' %>\nb").result == "a\nb" or raise
begin ERB.new("<%= 'a' -%>\nb").result; rescue SyntaxError ; else raise; end
ERB.new("<%= 'a' %>\nb" , nil, '-').result == "a\nb" or raise
ERB.new("<%= 'a' -%>\nb" , nil, '-').result == 'ab' or raise
ERB.new("<%= 'a' -%> \nb" , nil, '-').result == "a \nb" or raise
ERB.new("<%= 'a' -%>\n b" , nil, '-').result == 'a b' or raise
ERB.new("<%= 'a' -%>\n\nb", nil, '-').result == "a\nb" or raise
What is the difference between <%, <%=, <%# and -%> in ERB in Rails?的更多相关文章
- Ruby on Rails Tutorial读书笔记-1
只是怕忘了命令,全部撸一次,记个大概.. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 安装Ruby之前,先要安装RVM: curl -L https://get.rvm.io | bas ...
- Ruby学习笔记4: 动态web app的建立
Ruby学习笔记4: 动态web app的建立 We will first build the Categories page. This page contains topics like Art, ...
- (转)rvm安装与常用命令
rvm是一个命令行工具,可以提供一个便捷的多版本ruby环境的管理和切换. https://rvm.io/ 如果你打算学习ruby/rails, rvm是必不可少的工具之一. 这里所有的命令都是再用户 ...
- 声学感知刻度(mel scale、Bark scale、ERB)与声学特征提取(MFCC、BFCC、GFCC)
梅尔刻度 梅尔刻度(Mel scale)是一种由听众判断不同频率 音高(pitch)彼此相等的感知刻度,表示人耳对等距音高(pitch)变化的感知.mel 刻度和正常频率(Hz)之间的参考点是将1 k ...
- Java 堆内存与栈内存异同(Java Heap Memory vs Stack Memory Difference)
--reference Java Heap Memory vs Stack Memory Difference 在数据结构中,堆和栈可以说是两种最基础的数据结构,而Java中的栈内存空间和堆内存空间有 ...
- What's the difference between a stub and mock?
I believe the biggest distinction is that a stub you have already written with predetermined behavio ...
- [转载]Difference between <context:annotation-config> vs <context:component-scan>
在国外看到详细的说明一篇,非常浅显透彻.转给国内的筒子们:-) 原文标题: Spring中的<context:annotation-config>与<context:componen ...
- What's the difference between <b> and <strong>, <i> and <em> in HTML/XHTML? When should you use each?
ref:http://stackoverflow.com/questions/271743/whats-the-difference-between-b-and-strong-i-and-em The ...
- difference between forward and sendredirect
Difference between SendRedirect and forward is one of classical interview questions asked during jav ...
随机推荐
- urllib2
import urllib2response = urllib2.urlopen("http://www.baidu.com")print response.read() urlo ...
- ABBYY如何把图片转换成pdf格式
在制作工作文件的时候,有时候会遇到需要进行文件格式转换的情况,比较常见的文件格式转换就包含了Office与pdf格式之间的转换.但除此之外,图片与pdf格式也是可以进行转换的,那么图片要怎么操作,才能 ...
- hibernate--HQL语法与详细解释
HQL查询: Criteria查询对查询条件进行了面向对象封装,符合编程人员的思维方式,不过HQL(Hibernate Query Lanaguage)查询提供了更加丰富的和灵活的查询特性,因此 Hi ...
- nedb nodejs 数据库学习
// Type 1: In-memory only datastore (no need to load the database) var Datastore = require('nedb') ...
- ajax重构XMLHttpRequest
//重构XMLHttpRequestvar net = new Object(); //名字空間對象 net.READY_STATE_UNINITIALIZED = 0; net.READY_STAT ...
- AR增强现实特点、关键技术和应用
http://wenku.baidu.com/link?url=ABXxm5yezMIQRJUV7XvNWUe_QpUUdpQ3IxGRpYUa760iex1_bygCcTBvEhCMvrdLAmSX ...
- HTTP状态码对照表 HTTP response codes
当浏览者访问一个网页时,浏览者的浏览器会向网页所在服务器发出请求.当浏览器接收并显示网页前,此网页所在的服务器会返回一个包含HTTP状态码的信息头(server header)用以响应浏览器的请求. ...
- C语言常用的小代码
圆周率Pi tan(Pi/4)=1 => Pi=4*arctan(1) 反正切函数arctan()在C语言里表示为atan(),为保证精度取圆周率的代码如下: const double Pi = ...
- C# 常见集合之前的转换
1,从System.String[]转到List<System.String> System.String[] str={"str","string" ...
- lucene之排序、设置权重、优化、分布式搜索(转)
lucene之排序.设置权重.优化.分布式搜索(转) 1. 基本应用 using System;using System.Collections.Generic;using System.Text;u ...