blocks|key|2384362|text|[str1,+str2].reject+{%7Cx%7C+x==''}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|2384363|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>[str1, str2].reject {|x| x==''}
</code></pre>

blocks|key|765783|text|在ruby+1.9中|type|unstyled|depth|inlineStyleRanges|entityRanges|data|765784|[*(str1+unless+str1.empty?),+str2]|code-block|syntax|javascript|765785|ruby+1.8|765786|[(str1+unless+str1.empty?),+str2].compact|765787|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

In ruby 1.9

<pre><code>[*(str1 unless str1.empty?), str2]
</code></pre>

In ruby 1.8

<pre><code>[(str1 unless str1.empty?), str2].compact
</code></pre>

blocks|key|2668328|text|Object#tap|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2668329|[:starting_element].tap+do+%7Ca%7C
++a+<<+true+if+true
++a+<<+false+if+false
++a+<<+:for_sure
end
#+=>+[:starting_element,+true,+:for_sure]|code-block|syntax|javascript|2668330|所以在一行代码中|2668331|[].tap+{+%7Ca%7C+[foo,+bar].each+{+%7Cthing%7C+a+<<+thing+unless+thing.blank?+}+}
[bar].tap+{+%7Ca%7C+a+<<+bar+unless+foo.blank?+}|2668332|entityMap|0|LINK|mutability|MUTABLE|url|http://ruby-doc.org/core-2.3.0/Object.html#method-i-tap^0|0|A|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

<a href="http://ruby-doc.org/core-2.3.0/Object.html#method-i-tap" rel="noreferrer">Object#tap</a>

<pre><code>[:starting_element].tap do |a|
 a &lt;&lt; true if true
 a &lt;&lt; false if false
 a &lt;&lt; :for_sure
end
# =&gt; [:starting_element, true, :for_sure]
</code></pre>

So in one line

<pre><code>[].tap { |a| [foo, bar].each { |thing| a &lt;&lt; thing unless thing.blank? } }
[bar].tap { |a| a &lt;&lt; bar unless foo.blank? }
</code></pre>

blocks|key|765857|text|您可以使用delete_if|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|765858|['',+'hola'].delete_if(&:empty?)|code-block|syntax|javascript|765859|如果您使用的是Rails，则可以将empty?替换为blank?|765860|['',+'hola'].delete_if(&:blank?)|765861|或者使用块：|765862|['',+'hola'].delete_if{+%7Cx%7C+x+==+''+}|765863|entityMap^0|5|9|0|0|H|6|Q|6|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Y|8|@$9|Z|A|10|B|C]|$9|11|A|12|B|C]]|D|@]|E|$]]|$1|M|3|N|5|H|7|13|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|14|8|@]|D|@]|E|$]]|$1|Q|3|R|5|H|7|15|8|@]|D|@]|E|$I|J]]|$1|S|3|-4|5|6|7|16|8|@]|D|@]|E|$]]]|T|$]]

You can use delete_if:

<pre><code>['', 'hola'].delete_if(&amp;:empty?)
</code></pre>

If you're using Rails, you can replace empty? by blank?

<pre><code>['', 'hola'].delete_if(&amp;:blank?)
</code></pre>

or use a block:

<pre><code>['', 'hola'].delete_if{ |x| x == '' }
</code></pre>

blocks|key|2668284|text|另一种方式，|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2668285|(str1.present?+?+str1+:+[])+%2B+[str2]|code-block|syntax|javascript|2668286|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Another way, 

<pre><code>(str1.present? ? str1 : []) + [str2]
</code></pre>

blocks|key|2668366|text|也许是西里尔答案的一个更简洁的版本：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2668367|Array.new.tap+do+%7Carray%7C+++if+condition+++++array+<<+"foo"+++end+end|offset|length|style|CODE|2668368|entityMap^0|0|0|1W|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

Perhaps a more concise version of Cyril's answer:

<code>Array.new.tap do |array|
 if condition
 array &lt;&lt; "foo"
 end
end</code>

blocks|key|765997|text|一种更简洁的方法是使用presence，如果存在则返回对象，如果不存在则返回nil。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|765998|然后可以使用.compact剥离nil值|765999|[str1.presence,+str2].compact|code-block|syntax|javascript|766000|或者更好的是，神奇的*拆分运算符：|766001|[*str1.presence,+str2]|766002|(是的，双关语是有意的)|766003|entityMap|0|LINK|mutability|MUTABLE|url|https://www.rubydoc.info/docs/rails/Object:presence^0|B|8|12|3|B|8|0|0|6|8|G|3|0|0|A|1|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@$9|11|A|12|B|C]|$9|13|A|14|B|C]]|D|@$9|15|A|16|1|17]]|E|$]]|$1|F|3|G|5|6|7|18|8|@$9|19|A|1A|B|C]|$9|1B|A|1C|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|1D|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1E|8|@$9|1F|A|1G|B|C]]|D|@]|E|$]]|$1|O|3|P|5|J|7|1H|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|1I|8|@]|D|@]|E|$]]|$1|S|3|-4|5|6|7|1J|8|@]|D|@]|E|$]]]|T|$U|$5|V|W|X|E|$Y|Z]]]]

A more compact way to do this is using <a href="https://www.rubydoc.info/docs/rails/Object:presence" rel="nofollow noreferrer"><code>presence</code></a>, which returns the object if present, or <code>nil</code> if not.
<code>nil</code> values can then be stripped with <code>.compact</code>:
<pre><code>[str1.presence, str2].compact
</code></pre>
or even better, the magical <code>*</code> splat operator:
<pre><code>[*str1.presence, str2]
</code></pre>
(And yes, pun was intended)

blocks|key|765747|text|您可以使用三元语句：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|765748|ary+=+(str1.empty?)+?+[+str2+]+:+[+str1,+str2+]

str1+=+'';+str2+=+'bar'
(str1.empty?)+?+[+str2+]+:+[+str1,+str2+]+#=>+["bar"]
str1+=+'foo';+str2+=+'bar'
(str1.empty?)+?+[+str2+]+:+[+str1,+str2+]+#=>+["foo",+"bar"]|code-block|syntax|javascript|765749|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can use a ternary statement:

<pre><code>ary = (str1.empty?) ? [ str2 ] : [ str1, str2 ]

str1 = ''; str2 = 'bar'
(str1.empty?) ? [ str2 ] : [ str1, str2 ] #=&gt; ["bar"]
str1 = 'foo'; str2 = 'bar'
(str1.empty?) ? [ str2 ] : [ str1, str2 ] #=&gt; ["foo", "bar"]
</code></pre>

blocks|key|2384382|text|my_array+=+[str1,+str2].find_all{%7Citem%7C+item+!=+""}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|2384383|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>my_array = [str1, str2].find_all{|item| item != ""}
</code></pre>

blocks|key|4459709|text|您可以修补Aray+pr+Enumerable，并提供一个条件添加方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4459710|module+Array
+def+add_if(object,+condition=true)
+++self+<<+object+if+condition
+++return+self
+end
end|code-block|syntax|javascript|4459711|这样，它将是可链接的，保留了行中的大部分空间。array+=+[].add(:class,+is_given?).add(object,+false)+#etc|offset|length|style|CODE|4459712|entityMap^0|0|0|N|1L|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

You could monkey-patch Aray pr Enumerable and provide a conditional adding method.

<pre><code>module Array
 def add_if(object, condition=true)
 self &lt;&lt; object if condition
 return self
 end
end
</code></pre>

That way, it would be chainable, preserving most space in line.
<code>array = [].add(:class, is_given?).add(object, false) #etc</code>

blocks|key|2668489|text|请注意，sawa的Ruby1.9的proposed+answer+(目前投票最多的答案)在与散列一起使用时存在问题--如下所示；|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2668490|>+[*({foo:+1}+if+true),+{foo:+2}]
[
++++[0]+[
++++++++[0]+:foo,
++++++++[1]+1
++++],
++++[1]+{
++++++++:foo+=>+2
++++}
]|code-block|syntax|javascript|2668491|请注意，紧凑示例的工作方式与您预期的一样；|2668492|[({foo:+1}+if+true),+{foo:+2}].compact
[
++++[0]+{
++++++++:foo+=>+1
++++},
++++[1]+{
++++++++:foo+=>+2
++++}
]|2668493|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/6065567/3216868^0|H|F|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

Note that sawa's <a href="https://stackoverflow.com/a/6065567/3216868">proposed answer</a> for Ruby 1.9 (currently the answer with the most votes) has issues when used with a hash - as follows;
<pre class="lang-rb prettyprint-override"><code>&gt; [*({foo: 1} if true), {foo: 2}]
[
 [0] [
 [0] :foo,
 [1] 1
 ],
 [1] {
 :foo =&gt; 2
 }
]
</code></pre>
Note that the compact example works as you would expect;
<pre class="lang-rb prettyprint-override"><code>[({foo: 1} if true), {foo: 2}].compact
[
 [0] {
 :foo =&gt; 1
 },
 [1] {
 :foo =&gt; 2
 }
]
</code></pre>

blocks|key|2668537|text|在某种程度上，我觉得有两个不同的问题被问到：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2668538|2668539|是否有办法在一行中有条件地添加到数组？|ordered-list-item|2668540|如何完成此特定任务。|2668541|2668542|关于第一个问题:其他人已经提供了很多好的选择。但我没有特别提到的一点是，从技术上讲，您可以使用分号(;)作为内联语句分隔符，并且基本上可以在一行代码中编写您想要的任何内容。例如：|offset|length|style|CODE|2668543|array+=+[];+if+x;+array+<<+a;+elsif+y;+array+<<+b;+else;+array+<<+c;+end;+array|code-block|syntax|javascript|2668544|关于第二个问题:这里有一个有趣的选项，可以添加到列表中。使用chomp(separator)、split和reverse方法。|2668545|str1+=+""
str2+=+"bar"

"#{str2},#{str1}".chomp(",").split(",").reverse
#=>++["bar"]

str1+=+"foo"
str2+=+"bar"

"#{str2},#{str1}".chomp(",").split(",").reverse
#=>++["foo",+"bar"]|2668546|使用和不使用reverse的string.chomp(substring)可以非常方便地格式化字符串结果，否则需要使用一些条件语句来处理链中其他位置的相同操作。|2668547|entityMap^0|0|0|0|0|0|1E|1|0|0|U|G|1B|5|1H|7|0|0|6|7|E|N|0^^$0|@$1|2|3|4|5|6|7|11|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|12|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|13|8|@]|9|@]|A|$]]|$1|F|3|G|5|E|7|14|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|15|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|16|8|@$K|17|L|18|M|N]]|9|@]|A|$]]|$1|O|3|P|5|Q|7|19|8|@]|9|@]|A|$R|S]]|$1|T|3|U|5|6|7|1A|8|@$K|1B|L|1C|M|N]|$K|1D|L|1E|M|N]|$K|1F|L|1G|M|N]]|9|@]|A|$]]|$1|V|3|W|5|Q|7|1H|8|@]|9|@]|A|$R|S]]|$1|X|3|Y|5|6|7|1I|8|@$K|1J|L|1K|M|N]|$K|1L|L|1M|M|N]]|9|@]|A|$]]|$1|Z|3|-4|5|6|7|1N|8|@]|9|@]|A|$]]]|10|$]]

In a way, I feel like there are 2 different questions being asked:
<ol>
<li>Is there a way to conditionally add to an array in one line?</li>
<li>How do I achieve this specific task.</li>
</ol>
Regarding question #1:
Other people have already offered a lot of good options. One that I didn't see specifically mentioned though is that you can technically use a semicolon (<code>;</code>) as an inline statement separator and basically write whatever you want on a single line of code. For example:
<pre><code>array = []; if x; array &lt;&lt; a; elsif y; array &lt;&lt; b; else; array &lt;&lt; c; end; array
</code></pre>
Regarding question #2:
Here's a fun option to to add to the list. Use the <code>chomp(separator)</code>, <code>split</code>, and <code>reverse</code> methods.
<pre><code>str1 = &quot;&quot;
str2 = &quot;bar&quot;

&quot;#{str2},#{str1}&quot;.chomp(&quot;,&quot;).split(&quot;,&quot;).reverse
#=&gt; [&quot;bar&quot;]

str1 = &quot;foo&quot;
str2 = &quot;bar&quot;

&quot;#{str2},#{str1}&quot;.chomp(&quot;,&quot;).split(&quot;,&quot;).reverse
#=&gt; [&quot;foo&quot;, &quot;bar&quot;]
</code></pre>
<code>string.chomp(substring)</code> with and without <code>reverse</code> can be super handy ways to format string results that would otherwise need some conditional statements to handle the same operation somewhere else in the chain.

I have str1 and str2. str1 may or not be an empty string, and I want to construct an array like:

<pre><code>str1 = ""
str2 = "bar"
["bar"]
</code></pre>

or 

<pre><code>str1 = "foo"
str2 = "bar"
["foo", "bar"]
</code></pre>

I can only figure out a way to do this on two lines right now but I know there must be a way to do it one.

Is there a way to conditionally add to an array in one line?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

我有str1和str2。str1可能是空字符串，也可能不是，我想构造一个数组，如下所示：str1 = ""str2 = "bar"["bar"]或str1 = "foo"str2 = "bar"["foo", "bar"]我现在只能想出两行代码来做这件事，但我知道肯定有一种方法。

问有没有办法在一行中有条件地添加到数组中？
EN

回答 12

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问有没有办法在一行中有条件地添加到数组中？EN

回答 12

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问有没有办法在一行中有条件地添加到数组中？
EN