小编mu *_*ort的帖子

在Ruby gem的默认框架代码.gemspec中,Gem::Specification类中的文件有这一行:

spec.files = `git ls-files -z`.split("\x0") < - 请注意本问题末尾的PS

当我git ls-files -z在终端跑步时,我得到了

.gitignoreGemfileLICENSE.txtREADME.mdRakefiledogeify.gemspeclib/dogeify.rblib/dogeify/version.rb

这个.split("\x0")方法产生什么作为输出？

PS:参考第一行代码,``字符是否允许终端执行代码并将结果与​​Ruby方法结合起来？

假设我有下表(称为文件表),文件名为:

file
something.h
something.cc
somethingelse.js
something.py
something.xkh
something.jpeg

我尝试了以下查询:

select file 
  from filetable
    where file ~ E'\.[cc|h|js|py]';

查询输出是:

file
something.h
something.cc
somethingelse.js
something.py
something.xkh
something.jpeg

但是,我只需要完全使用.cc,.h,.js,.py完成的文件.如何改进此查询？

基本上我要做的是使用下划线js编译带有一些数据的模板.我的代码如下:

var temp = "<div> Hello <%=names%> </div>";
var html = _.template(temp, {names:'world'};

我期待我的变量html

<div> Hello world </div> 

但由于某些原因,变量名称未定义,而编译和模板永远不会编译.

这是下划线js最基本的东西,根据文档和Web上的大量示例,它应该工作.我究竟做错了什么？

如何用javascript中的下划线替换字符串中的每个字母.

例如,我希望将"name"字符串替换为_ _ _ _.

有没有办法我可以指定字母az并用下划线替换它.

提前致谢.

我看到一个here-document用作参数,里面有方括号运算符.它看起来像:

method(<<EOF)[0][0]
lots of text
EOF

方括号运算符的含义可能是什么？有谁知道那是什么样的成语？

我想在我的控制台中调用它（ap是很棒的打印宝石）：

ap Purchase.last(10)

但我收到此错误：

ActionController::UnfilteredParameters: unable to convert unpermitted parameters to hash

它的工作原理如下：

irb(main):020:0> ap Purchase.last
#<Purchase:0x00007f86b792a320> {
                              :id => 28445,
                         :user_id => 10177,
                      :product_id => nil,
                    :product_type => nil,
                           :price => 9.0,
                    :gateway_code => nil,
                     :gateway_msg => nil,
                :gateway_response => nil,
                      :created_at => Fri, 18 May 2018 22:20:10 UTC +00:00,
                      :updated_at => Fri, 18 May 2018 22:20:10 UTC +00:00,
                  :checkout_total => 9.0,
                      :successful => true,
                         :cart_id => 17242,
                   :report_errors => nil,
    :transacted_value_of_products => 9.0,
            :comp_credits_applied => 0.0 …

所以,假设我有一系列字符串,例如:["74712 Don","48342 Cindy","50912 Nick"],我想按照名字前面的数字对它们进行排序.我如何只按每个元素的前5个字符排序(同时还将它们作为数字进行评估)？谢谢

我在使用 Ubuntu + Apache +Passenger 时遇到此错误。问题是我没有使用任何数据库或模型。

undefined method `has_one_attached' for #<Class:0x0000555c6ad94fd8> (NoMethodError)
  /usr/local/rvm/gems/ruby-2.5.1/gems/activerecord-5.2.1/lib/active_record/dynamic_matchers.rb:22:in `method_missing'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activestorage-5.2.1/app/models/active_storage/blob/representable.rb:7:in `block in <module:Representable>'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activesupport-5.2.1/lib/active_support/concern.rb:122:in `class_eval'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activesupport-5.2.1/lib/active_support/concern.rb:122:in `append_features'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activestorage-5.2.1/app/models/active_storage/blob.rb:23:in `include'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activestorage-5.2.1/app/models/active_storage/blob.rb:23:in `<class:Blob>'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activestorage-5.2.1/app/models/active_storage/blob.rb:16:in `<main>'
  /usr/local/rvm/gems/ruby-2.5.1/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require'
  /usr/local/rvm/gems/ruby-2.5.1/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `block in require_with_bootsnap_lfi'
  /usr/local/rvm/gems/ruby-2.5.1/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/loaded_features_index.rb:83:in `register'
  /usr/local/rvm/gems/ruby-2.5.1/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:20:in `require_with_bootsnap_lfi'
  /usr/local/rvm/gems/ruby-2.5.1/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:29:in `require'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activesupport-5.2.1/lib/active_support/dependencies.rb:287:in `block in require'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activesupport-5.2.1/lib/active_support/dependencies.rb:253:in `load_dependency'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activesupport-5.2.1/lib/active_support/dependencies.rb:287:in `require'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activesupport-5.2.1/lib/active_support/dependencies.rb:374:in `block in require_or_load'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activesupport-5.2.1/lib/active_support/dependencies.rb:37:in `block in load_interlock'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activesupport-5.2.1/lib/active_support/dependencies/interlock.rb:14:in `block in loading'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activesupport-5.2.1/lib/active_support/concurrency/share_lock.rb:151:in `exclusive'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activesupport-5.2.1/lib/active_support/dependencies/interlock.rb:13:in `loading'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activesupport-5.2.1/lib/active_support/dependencies.rb:37:in `load_interlock'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activesupport-5.2.1/lib/active_support/dependencies.rb:352:in `require_or_load'
  /usr/local/rvm/gems/ruby-2.5.1/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/active_support.rb:48:in `block in require_or_load'
  /usr/local/rvm/gems/ruby-2.5.1/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/active_support.rb:16:in `allow_bootsnap_retry'
  /usr/local/rvm/gems/ruby-2.5.1/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/active_support.rb:47:in `require_or_load'
  /usr/local/rvm/gems/ruby-2.5.1/gems/activesupport-5.2.1/lib/active_support/dependencies.rb:330:in `depend_on'
  /usr/local/rvm/gems/ruby-2.5.1/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/active_support.rb:82:in `depend_on' …

我的 rspec 线

allow_any_instance_of(School).to receive(:admission).and_return(:body)

lib/school.rb 我的模块学校中有我的录取方法

def self.admission()

像这样，但是当我运行 rspec 时，它会抛出类似的错误

Failure/Error: allow_any_instance_of(School).to receive(:admission),and_return(:body)
       School does not implement #admission

In go, why there is no function which directly calculates absolute value for integer datatypes. Currently all integer values has to be type casted to float64 and then it has to be used as a parameter in math.Abs() function. And it returns float64 datatype only, which again has to be type casted into integer datatype.

Like this code is giving error as Go is statically typed language, so does not allows different datatype.

./prog.go:12:39: cannot use x (type int64) as …

使用 PostgreSQL 8.1.11，有没有办法选择一组名称以相同前缀开头的列。

假设我们有列：PREFIX_col1、PREFIX_col2、...

是否可以执行如下请求：

SELECT 'PREFIX_*' FROM mytable;

这当然是行不通的。

我仍在学习 Ruby，并且正在练习基本网站的get路线和post请求、用户登录、登录等，我遇到了一种“slug”方法：

def slug
    self.username.strip.downcase.gsub(" ","-")
  end

我尝试使用 irb 来尝试找出 gsub 正在做什么：

"hello".gsub(" ","-")

但它只是给了我：

"hello"

我尝试在数组上使用它，但效果不佳。

但我的问题是 gsub 到底在这里做什么？gsub 一般是什么？这种方法的结果是什么？

提前致谢！

这是我的代码,我正在获取错误查询mssg:

 $name = mysqli_real_escape_string($dbc, trim($_POST['fname']));
 $emailid = mysqli_real_escape_string($dbc, trim($_POST['emailid']));
 $city = mysqli_real_escape_string($dbc, trim($_POST['city']));
 $comment = mysqli_real_escape_string($dbc, trim($_POST['comment']));
 $query="INSERT INTO userdate('name','city','emailid','pledge','date') VALUES       ('$name','$city','$emailid','$comment',NOW())";
$result=mysqli_query($dbc, $query) or die('error query');