实际上,我用Google搜索了一段时间但没有成功.这对我来说太抽象了.无论如何,我的英语被打破了.我想知道的是两点如下:什么是反向换行？反向换行和换行有什么区别？那么,有没有人可以给我一个例子或作出解释？非常感谢你.PS:我在这里是发票.我不知道我是否为你说清楚了.
有没有人可以看看.我对此感到困惑.非常感谢你.
[river@localhost demo04]$ rake db:migrate --trace
WARNING: 'require 'rake/rdoctask'' is deprecated. Please use 'require 'rdoc/task' (in RDoc 2.4.2+)' instead.
at /home/river/.rvm/gems/ruby-1.8.7-p358@global/gems/rake-0.9.2.2/lib/rake/rdoctask.rb
** Invoke db:migrate (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute db:migrate
== CreateProducts: migrating =================================================
-- create_table(:products)
rake aborted!
An error has occurred, all later migrations canceled:
private method `test' called for #<ActiveRecord::ConnectionAdapters::TableDefinition:0x7f2a8fb07c30>
./db/migrate//20120628020339_create_products.rb:5:in `up_without_benchmarks'
/home/river/.rvm/gems/ruby-1.8.7-p358/gems/activerecord-2.2.2/lib/active_record/connection_adapters/abstract/schema_statements.rb:104:in `create_table'
/home/river/.rvm/gems/ruby-1.8.7-p358/gems/activerecord-2.2.2/lib/active_record/connection_adapters/mysql_adapter.rb:445:in `create_table'
/home/river/.rvm/gems/ruby-1.8.7-p358/gems/activerecord-2.2.2/lib/active_record/migration.rb:346:in `send'
/home/river/.rvm/gems/ruby-1.8.7-p358/gems/activerecord-2.2.2/lib/active_record/migration.rb:346:in `method_missing'
/home/river/.rvm/gems/ruby-1.8.7-p358/gems/activerecord-2.2.2/lib/active_record/migration.rb:326:in `say_with_time'
/home/river/.rvm/rubies/ruby-1.8.7-p358/lib/ruby/1.8/benchmark.rb:293:in `measure'
/home/river/.rvm/gems/ruby-1.8.7-p358/gems/activerecord-2.2.2/lib/active_record/migration.rb:326:in `say_with_time'
/home/river/.rvm/gems/ruby-1.8.7-p358/gems/activerecord-2.2.2/lib/active_record/migration.rb:342:in `method_missing'
./db/migrate//20120628020339_create_products.rb:3:in `up_without_benchmarks'
/home/river/.rvm/gems/ruby-1.8.7-p358/gems/activerecord-2.2.2/lib/active_record/migration.rb:280:in `send'
/home/river/.rvm/gems/ruby-1.8.7-p358/gems/activerecord-2.2.2/lib/active_record/migration.rb:280:in …我认为它应该提醒4次,但为什么它只提醒了2次.有人能为我解释一下吗？
var arr = new Array;
arr.push("1");
arr.push("2");
arr.push("3");
arr.push("4");
for(var i=0;i<arr.length;i++){
alert(arr.pop());
}