blocks|key|3303228|text|就我个人而言，我会为函数引用设置一个散列，然后使用该字符串作为散列的索引。然后使用它的参数调用函数引用。这样做的好处是不允许错误的字符串调用您不想调用的东西。另一种方法基本上是对字符串进行eval。不要这样做。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3303229|另外，不要偷懒，实际上输入你的整个问题，而不是链接到一些东西。|3303230|entityMap|0|LINK|mutability|MUTABLE|url|http://snippets.dzone.com/posts/show/5188^0|2M|4|2M|4|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@$9|S|A|T|1|U]]|E|$]]|$1|F|3|G|5|6|7|V|8|@]|D|@]|E|$]]|$1|H|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]]]

<p>Personally I would setup a hash to function references and then use the string as an index to the hash. You then call the function reference with it's parameters. This has the advantage of not allowing the wrong string to call something you don't want to call. The other way is to basically <a href="http://snippets.dzone.com/posts/show/5188" rel="nofollow noreferrer"><code>eval</code></a> the string. Do not do this.</p>

<p>PS don't be lazy and actually type out your whole question, instead of linking to something.</p>


blocks|key|328988|text|直接在对象上调用函数|type|unstyled|depth|inlineStyleRanges|entityRanges|data|328989|a+=+[2,+2,+3]
a.send("length")
#+or
a.public_send("length")|code-block|syntax|javascript|328990|，如预期的那样返回3|328991|或者用于模块函数|328992|FileUtils.send('pwd')
#+or
FileUtils.public_send(:pwd)|328993|和本地定义的方法|328994|def+load()
++++puts+"load()+function+was+executed."
end

send('load')
#+or
public_send('load')|328995|文档：|328996|328997|Object#public_send|unordered-list-item|offset|length|style|CODE|328998|Object#send|328999|329000|entityMap|0|LINK|mutability|MUTABLE|url|http://ruby-doc.org/core/Object.html#method-i-public_send|1|http://ruby-doc.org/core/Object.html#method-i-send^0|0|0|0|0|0|0|0|0|0|0|I|0|I|0|0|0|B|0|B|1|0|0^^$0|@$1|2|3|4|5|6|7|1D|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|1E|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|1F|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|1G|8|@]|9|@]|A|$]]|$1|K|3|L|5|D|7|1H|8|@]|9|@]|A|$E|F]]|$1|M|3|N|5|6|7|1I|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|1J|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|1K|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1L|8|@]|9|@]|A|$]]|$1|T|3|U|5|V|7|1M|8|@$W|1N|X|1O|Y|Z]]|9|@$W|1P|X|1Q|1|1R]]|A|$]]|$1|10|3|11|5|V|7|1S|8|@$W|1T|X|1U|Y|Z]]|9|@$W|1V|X|1W|1|1X]]|A|$]]|$1|12|3|-4|5|6|7|1Y|8|@]|9|@]|A|$]]|$1|13|3|-4|5|6|7|1Z|8|@]|9|@]|A|$]]]|14|$15|$5|16|17|18|A|$19|1A]]|1B|$5|16|17|18|A|$19|1C]]]]

<p>To call functions directly on an object</p>

<pre><code>a = [2, 2, 3]
a.send("length")
# or
a.public_send("length")
</code></pre>

<p>which returns 3 as expected</p>

<p>or for a module function</p>

<pre><code>FileUtils.send('pwd')
# or
FileUtils.public_send(:pwd)
</code></pre>

<p>and a locally defined method </p>

<pre><code>def load()
    puts "load() function was executed."
end

send('load')
# or
public_send('load')
</code></pre>

<p>Documentation:</p>

<ul>
<li><a href="http://ruby-doc.org/core/Object.html#method-i-public_send" rel="noreferrer"><code>Object#public_send</code></a></li>
<li><a href="http://ruby-doc.org/core/Object.html#method-i-send" rel="noreferrer"><code>Object#send</code></a></li>
</ul>


blocks|key|3303318|text|使用以下命令：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3303319|>+a+=+"my_string"
>+meth+=+a.method("size")
>+meth.call()+#+call+the+size+method
=>+9|code-block|syntax|javascript|3303320|很简单，对吧？|3303321|至于全局变量，我认为Ruby的方法应该是使用methods方法进行搜索。|offset|length|style|CODE|3303322|entityMap^0|0|0|0|M|7|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|T|8|@$K|U|L|V|M|N]]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

<p>Use this:</p>

<pre><code>&gt; a = "my_string"
&gt; meth = a.method("size")
&gt; meth.call() # call the size method
=&gt; 9
</code></pre>

<p>Simple, right?</p>

<p>As for the <em>global</em>, I think the Ruby way would be to search it using the <code>methods</code> method.</p>


blocks|key|3303402|text|三种方式：send+/+call+/+eval+-及其基准测试|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3303403|典型调用(供参考)：|3303404|s=+"hi+man"
s.length+#=>+6|code-block|syntax|javascript|3303405|使用send|3303406|s.send(:length)+#=>+6|3303407|使用call|3303408|method_object+=+s.method(:length)+
p+method_object.call+#=>+6|3303409|使用eval|3303410|eval+"s.length"+#=>+6|3303411|基准测试|3303412|require+"benchmark"+
test+=+"hi+man"+
m+=+test.method(:length)+
n+=+100000+
Benchmark.bmbm+{%7Cx%7C+
++x.report("call")+{+n.times+{+m.call+}+}+
++x.report("send")+{+n.times+{+test.send(:length)+}+}+
++x.report("eval")+{+n.times+{+eval+"test.length"+}+}+
}+|3303413|你可以看到，实例化一个方法对象是调用一个方法的最快的动态方式，还要注意使用|3303414|的速度有多慢。|blockquote|3303415|3303416|3303417|#######################################
#####+++The+results
#######################################
#Rehearsal+----------------------------------------
#call+++0.050000+++0.020000+++0.070000+(++0.077915)
#send+++0.080000+++0.000000+++0.080000+(++0.086071)
#eval+++0.360000+++0.040000+++0.400000+(++0.405647)
#-------------------------------+total:+0.550000sec

#++++++++++user+++++system++++++total++++++++real
#call+++0.050000+++0.020000+++0.070000+(++0.072041)
#send+++0.070000+++0.000000+++0.070000+(++0.077674)
#eval+++0.370000+++0.020000+++0.390000+(++0.399442)|3303418|功劳归功于这篇blog+post，它详细介绍了这三种方法，并展示了如何检查这些方法是否存在。|3303419|entityMap|0|LINK|mutability|MUTABLE|url|http://blog.khd.me/ruby/ruby-dynamic-method-calling/^0|5|4|C|4|J|4|0|0|0|2|4|0|0|2|4|0|0|2|4|0|0|0|0|0|0|0|0|0|7|9|0|0^^$0|@$1|2|3|4|5|6|7|1L|8|@$9|1M|A|1N|B|C]|$9|1O|A|1P|B|C]|$9|1Q|A|1R|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|1S|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|1T|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1U|8|@$9|1V|A|1W|B|C]]|D|@]|E|$]]|$1|O|3|P|5|J|7|1X|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|1Y|8|@$9|1Z|A|20|B|C]]|D|@]|E|$]]|$1|S|3|T|5|J|7|21|8|@]|D|@]|E|$K|L]]|$1|U|3|V|5|6|7|22|8|@$9|23|A|24|B|C]]|D|@]|E|$]]|$1|W|3|X|5|J|7|25|8|@]|D|@]|E|$K|L]]|$1|Y|3|Z|5|6|7|26|8|@]|D|@]|E|$]]|$1|10|3|11|5|J|7|27|8|@]|D|@]|E|$K|L]]|$1|12|3|13|5|6|7|28|8|@]|D|@]|E|$]]|$1|14|3|15|5|16|7|29|8|@]|D|@]|E|$]]|$1|17|3|-4|5|6|7|2A|8|@]|D|@]|E|$]]|$1|18|3|-4|5|6|7|2B|8|@]|D|@]|E|$]]|$1|19|3|1A|5|J|7|2C|8|@]|D|@]|E|$K|L]]|$1|1B|3|1C|5|6|7|2D|8|@]|D|@$9|2E|A|2F|1|2G]]|E|$]]|$1|1D|3|-4|5|6|7|2H|8|@]|D|@]|E|$]]]|1E|$1F|$5|1G|1H|1I|E|$1J|1K]]]]

<h2>Three Ways: <code>send</code> / <code>call</code> / <code>eval</code> - and their Benchmarks</h2>
<p>Typical invocation (for reference):</p>
<pre><code>s= &quot;hi man&quot;
s.length #=&gt; 6
</code></pre>
<h3>Using <code>send</code></h3>
<pre><code>s.send(:length) #=&gt; 6
</code></pre>
<h3>Using <code>call</code></h3>
<pre><code>method_object = s.method(:length) 
p method_object.call #=&gt; 6
</code></pre>
<h3>Using <code>eval</code></h3>
<pre><code>eval &quot;s.length&quot; #=&gt; 6
</code></pre>
<p> </p>
<h2>Benchmarks</h2>
<pre><code>require &quot;benchmark&quot; 
test = &quot;hi man&quot; 
m = test.method(:length) 
n = 100000 
Benchmark.bmbm {|x| 
  x.report(&quot;call&quot;) { n.times { m.call } } 
  x.report(&quot;send&quot;) { n.times { test.send(:length) } } 
  x.report(&quot;eval&quot;) { n.times { eval &quot;test.length&quot; } } 
} 
</code></pre>
<blockquote>
<p>...as you can see, instantiating a method object is the fastest dynamic way in calling a method, also notice how slow using eval is.</p>
</blockquote>
<pre><code>#######################################
#####   The results
#######################################
#Rehearsal ----------------------------------------
#call   0.050000   0.020000   0.070000 (  0.077915)
#send   0.080000   0.000000   0.080000 (  0.086071)
#eval   0.360000   0.040000   0.400000 (  0.405647)
#------------------------------- total: 0.550000sec

#          user     system      total        real
#call   0.050000   0.020000   0.070000 (  0.072041)
#send   0.070000   0.000000   0.070000 (  0.077674)
#eval   0.370000   0.020000   0.390000 (  0.399442)
</code></pre>
<p>Credit goes to this <a href="http://blog.khd.me/ruby/ruby-dynamic-method-calling/" rel="noreferrer">blog post</a> which elaborates a bit more on the three methods and also shows how to check if the methods exist.</p>


<p>How can I do what they are talking about <a href="https://stackoverflow.com/questions/3061/calling-a-function-from-a-string-with-the-functions-name-in-python">here</a>, but in Ruby?</p>

<p>How would you do the function on an object? and how would you do a global function (see jetxee's <a href="https://stackoverflow.com/questions/3061/calling-a-function-from-a-string-with-the-functions-name-in-python/834451#834451">answer</a> on the post mentioned)?</p>

<p><strong>EXAMPLE CODE:</strong></p>

<pre><code>event_name = "load"

def load()
  puts "load() function was executed."
end

def row_changed()
  puts "row_changed() function was executed."
end 

#something here to see that event_name = "load" and run load()
</code></pre>

<p><strong>UPDATE:</strong>
How do you get to the global methods? or my global functions?</p>

<p>I tried this additional line  </p>

<pre><code>puts methods
</code></pre>

<p>and load and row_change where not listed. </p>


Calling a Method From a String With the Method's Name in Ruby

Ruby语言

我怎么才能做到他们所说的，而不是Ruby语言？您将如何在对象上执行该函数？你将如何做一个全局函数(参见jetxee的 )？示例代码：event_name = "load"def load()  puts "load() function was executed."enddef row_changed()  puts ...

问在Ruby中调用带有方法名称的字符串中的方法
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