blocks|key|343801|text|my_hash.each+{+%7Ck,+v%7C+my_hash[k]+=+v.upcase+}+|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|343802|或者，如果您希望以非破坏性方式执行此操作，并返回一个新的散列，而不是修改my_hash|unstyled|offset|length|style|CODE|343803|a_new_hash+=+my_hash.inject({})+{+%7Ch,+(k,+v)%7C+h[k]+=+v.upcase;+h+}+|343804|这个最后的版本有一个额外的好处，那就是你也可以转换密钥。|343805|entityMap^0|0|10|7|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|R|8|@$G|S|H|T|I|J]]|9|@]|A|$]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$B|C]]|$1|M|3|N|5|F|7|V|8|@]|9|@]|A|$]]|$1|O|3|-4|5|F|7|W|8|@]|9|@]|A|$]]]|P|$]]

<pre><code>my_hash.each { |k, v| my_hash[k] = v.upcase } 
</code></pre>

or, if you'd prefer to do it non-destructively, and return a new hash instead of modifying <code>my_hash</code>:

<pre><code>a_new_hash = my_hash.inject({}) { |h, (k, v)| h[k] = v.upcase; h } 
</code></pre>

This last version has the added benefit that you could transform the keys too.

blocks|key|343089|text|由于ruby+2.4.0，您可以使用本机Hash#transform_values方法：|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|CODE|entityRanges|data|343090|hash+=+{"a"+=>+"b",+"c"+=>+"d"}
new_hash+=+hash.transform_values(&:upcase)
#+=>+{"a"+=>+"B",+"c"+=>+"D"}|code-block|syntax|javascript|343091|还有破坏性的Hash#transform_values!版本。|343092|entityMap|0|LINK|mutability|MUTABLE|url|https://ruby-doc.org/core-2.4.0/Hash.html#method-i-transform_values|1|https://ruby-doc.org/core-2.4.0/Hash.html#method-i-transform_values-21^0|2|A|2|A|K|L|K|L|0|0|0|6|M|6|M|1|0^^$0|@$1|2|3|4|5|6|7|X|8|@$9|Y|A|Z|B|C]|$9|10|A|11|B|D]|$9|12|A|13|B|D]]|E|@$9|14|A|15|1|16]]|F|$]]|$1|G|3|H|5|I|7|17|8|@]|E|@]|F|$J|K]]|$1|L|3|M|5|6|7|18|8|@$9|19|A|1A|B|D]]|E|@$9|1B|A|1C|1|1D]]|F|$]]|$1|N|3|-4|5|6|7|1E|8|@]|E|@]|F|$]]]|O|$P|$5|Q|R|S|F|$T|U]]|V|$5|Q|R|S|F|$T|W]]]]

Since <code>ruby 2.4.0</code> you can use native <a href="https://ruby-doc.org/core-2.4.0/Hash.html#method-i-transform_values" rel="noreferrer"><code>Hash#transform_values</code></a> method:

<pre><code>hash = {"a" =&gt; "b", "c" =&gt; "d"}
new_hash = hash.transform_values(&amp;:upcase)
# =&gt; {"a" =&gt; "B", "c" =&gt; "D"}
</code></pre>

There is also destructive <a href="https://ruby-doc.org/core-2.4.0/Hash.html#method-i-transform_values-21" rel="noreferrer"><code>Hash#transform_values!</code></a> version.

blocks|key|342998|text|您可以收集这些值，并再次将其从Array转换为Hash。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|342999|如下所示：|343000|config+=+Hash[+config.collect+{%7Ck,v%7C+[k,+v.upcase]+}+]|code-block|syntax|javascript|343001|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You can collect the values, and convert it from Array to Hash again.

Like this:

<pre><code>config = Hash[ config.collect {|k,v| [k, v.upcase] } ]
</code></pre>

blocks|key|343870|text|这样就可以了：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|343871|my_hash.each_with_object({})+{+%7C(key,+value),+hash%7C+hash[key]+=+value.upcase+}|code-block|syntax|javascript|343872|与inject相反，它的优点是您不需要在块中再次返回散列。|offset|length|style|CODE|343873|entityMap^0|0|0|1|6|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|$]]

This will do it:

<pre><code>my_hash.each_with_object({}) { |(key, value), hash| hash[key] = value.upcase }
</code></pre>

As opposed to <code>inject</code> the advantage is that you are in no need to return the hash again inside the block.

blocks|key|346461|text|在ActiveSupport+v4.2.0中有一个这样的方法。它被称为transform_values，基本上只是为每个键值对执行一个块。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|346462|由于他们使用的是each，所以我认为没有比循环更好的方法了。|346463|hash+=+{sample:+'gach'}

result+=+{}
hash.each+do+%7Ckey,+value%7C
++result[key]+=+do_stuff(value)
end|code-block|syntax|javascript|346464|更新：|BOLD|346465|从Ruby2.4.0开始，你可以在本地使用#transform_values和#transform_values!。|346466|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/rails/rails/blob/v4.2.0/activesupport/lib/active_support/core_ext/hash/transform_values.rb|1|https://ruby-doc.org/core-2.4.0/Hash.html#method-i-transform_values|2|https://ruby-doc.org/core-2.4.0/Hash.html#method-i-transform_values-21^0|Z|G|Z|G|0|0|8|4|0|0|0|3|0|L|H|13|I|L|H|1|13|I|2|0^^$0|@$1|2|3|4|5|6|7|13|8|@$9|14|A|15|B|C]]|D|@$9|16|A|17|1|18]]|E|$]]|$1|F|3|G|5|6|7|19|8|@$9|1A|A|1B|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|1C|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1D|8|@$9|1E|A|1F|B|O]]|D|@]|E|$]]|$1|P|3|Q|5|6|7|1G|8|@$9|1H|A|1I|B|C]|$9|1J|A|1K|B|C]]|D|@$9|1L|A|1M|1|1N]|$9|1O|A|1P|1|1Q]]|E|$]]|$1|R|3|-4|5|6|7|1R|8|@]|D|@]|E|$]]]|S|$T|$5|U|V|W|E|$X|Y]]|Z|$5|U|V|W|E|$X|10]]|11|$5|U|V|W|E|$X|12]]]]

There's a method for that in ActiveSupport v4.2.0. It's called <a href="https://github.com/rails/rails/blob/v4.2.0/activesupport/lib/active_support/core_ext/hash/transform_values.rb" rel="nofollow noreferrer"><code>transform_values</code></a> and basically just executes a block for each key-value-pair.

Since they're doing it with a <code>each</code> I think there's no better way than to loop through.

<pre class="lang-rb prettyprint-override"><code>hash = {sample: 'gach'}

result = {}
hash.each do |key, value|
 result[key] = do_stuff(value)
end
</code></pre>

Update:

Since Ruby 2.4.0 you can natively use <a href="https://ruby-doc.org/core-2.4.0/Hash.html#method-i-transform_values" rel="nofollow noreferrer"><code>#transform_values</code></a> and <a href="https://ruby-doc.org/core-2.4.0/Hash.html#method-i-transform_values-21" rel="nofollow noreferrer"><code>#transform_values!</code></a>.

blocks|key|342940|text|尝试此函数：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|342941|h+=+{"a"+=>+"b",+"c"+=>+"d"}
h.each{%7Ci,j%7C+j.upcase!}+#+now+contains+{"a"+=>+"B",+"c"+=>+"D"}.|code-block|syntax|javascript|342942|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|$]]

Try this function:

<pre><code>h = {"a" =&gt; "b", "c" =&gt; "d"}
h.each{|i,j| j.upcase!} # now contains {"a" =&gt; "B", "c" =&gt; "D"}.
</code></pre>

blocks|key|3328318|text|您可能希望更进一步，在嵌套的散列上执行此操作。当然，这种情况在Rails项目中经常发生。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3328319|下面是一些确保params散列采用UTF-8格式的代码：|3328320|++def+convert_hash+hash
++++hash.inject({})+do+%7Ch,(k,v)%7C
++++++if+v.kind_of?+String
++++++++h[k]+=+to_utf8(v)+
++++++else
++++++++h[k]+=+convert_hash(v)
++++++end
++++++h
++++end++++++
++end++++

++#+Iconv+UTF-8+helper
++#+Converts+strings+into+valid+UTF-8
++#
++#+@param+[String]+untrusted_string+the+string+to+convert+to+UTF-8
++#+@return+[String]+your+string+in+UTF-8
++def+to_utf8+untrusted_string=""
++++ic+=+Iconv.new('UTF-8//IGNORE',+'UTF-8')
++++ic.iconv(untrusted_string+%2B+'+')[0..-2]
++end++|code-block|syntax|javascript|3328321|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You may want to go a step further and do this on a nested hash. Certainly this happens a fair amount with Rails projects. 

Here's some code to ensure a params hash is in UTF-8:

<pre><code> def convert_hash hash
 hash.inject({}) do |h,(k,v)|
 if v.kind_of? String
 h[k] = to_utf8(v) 
 else
 h[k] = convert_hash(v)
 end
 h
 end 
 end 

 # Iconv UTF-8 helper
 # Converts strings into valid UTF-8
 #
 # @param [String] untrusted_string the string to convert to UTF-8
 # @return [String] your string in UTF-8
 def to_utf8 untrusted_string=""
 ic = Iconv.new('UTF-8//IGNORE', 'UTF-8')
 ic.iconv(untrusted_string + ' ')[0..-2]
 end 
</code></pre>

blocks|key|342968|text|我这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|342969|342970|+new_hash+=哈希[*original_hash.collect{%7C+key，value%7C+key，value+%2B+1}.flatten]|blockquote|342971|342972|342973|这也为您提供了通过任何表达式转换键或值的工具(当然，它是非破坏性的)。|342974|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|M|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|N|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|O|8|@]|9|@]|A|$]]|$1|G|3|-4|5|6|7|P|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|Q|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|R|8|@]|9|@]|A|$]]]|K|$]]

I do something like this:

<blockquote>
 new_hash = Hash[*original_hash.collect{|key,value| [key,value + 1]}.flatten]
</blockquote>

This provides you with the facilities to transform the key or value via any expression also (and it's non-destructive, of course).

blocks|key|341600|text|Ruby有tap方法(1.8.7、1.9.3和2.1.0)，它对这样的东西非常有用。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|341601|original_hash+=+{+:a+=>+'a',+:b+=>+'b'+}
original_hash.clone.tap{+%7Ch%7C+h.each{+%7Ck,v%7C+h[k]+=+v.upcase+}+}
#+=>+{:a=>"A",+:b=>"B"}
original_hash+#+=>+{:a=>"a",+:b=>"b"}|code-block|syntax|javascript|341602|entityMap|0|LINK|mutability|MUTABLE|url|http://ruby-doc.org/core-1.8.7/Object.html#method-i-tap|1|http://ruby-doc.org/core-1.9.3/Object.html#method-i-tap|2|http://ruby-doc.org/core-2.1.0/Object.html#method-i-tap^0|5|3|B|5|0|H|5|1|N|5|2|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]]|D|@$9|Z|A|10|1|11]|$9|12|A|13|1|14]|$9|15|A|16|1|17]]|E|$]]|$1|F|3|G|5|H|7|18|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|19|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]|S|$5|N|O|P|E|$Q|T]]|U|$5|N|O|P|E|$Q|V]]]]

Ruby has the <code>tap</code> method (<a href="http://ruby-doc.org/core-1.8.7/Object.html#method-i-tap" rel="nofollow">1.8.7</a>, <a href="http://ruby-doc.org/core-1.9.3/Object.html#method-i-tap" rel="nofollow">1.9.3</a> and <a href="http://ruby-doc.org/core-2.1.0/Object.html#method-i-tap" rel="nofollow">2.1.0</a>) that's very useful for stuff like this.

<pre><code>original_hash = { :a =&gt; 'a', :b =&gt; 'b' }
original_hash.clone.tap{ |h| h.each{ |k,v| h[k] = v.upcase } }
# =&gt; {:a=&gt;"A", :b=&gt;"B"}
original_hash # =&gt; {:a=&gt;"a", :b=&gt;"b"}
</code></pre>

blocks|key|343891|text|Rails-specific|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|343892|如果有人只需要对每个值调用to_s方法，并且没有使用Rails+4.2+(包括transform_values方法link)，您可以执行以下操作：|CODE|343893|original_hash+=+{+:a+=>+'a',+:b+=>+BigDecimal('23.4')+}
#=>+{:a=>"a",+:b=>#<BigDecimal:5c03a00,'0.234E2',18(18)>}
JSON(original_hash.to_json)
#=>+{"a"=>"a",+"b"=>"23.4"}|code-block|syntax|javascript|343894|注意:需要使用'json‘库。|343895|注意2:这也会把关键字转换成字符串|343896|entityMap|0|LINK|mutability|MUTABLE|url|http://www.justinweiss.com/blog/2014/08/25/the-lesser-known-features-in-rails-4-dot-2/^0|0|E|0|D|4|13|G|1L|4|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Z|8|@$9|10|A|11|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|12|8|@$9|13|A|14|B|H]|$9|15|A|16|B|H]]|D|@$9|17|A|18|1|19]]|E|$]]|$1|I|3|J|5|K|7|1A|8|@]|D|@]|E|$L|M]]|$1|N|3|O|5|6|7|1B|8|@]|D|@]|E|$]]|$1|P|3|Q|5|6|7|1C|8|@]|D|@]|E|$]]|$1|R|3|-4|5|6|7|1D|8|@]|D|@]|E|$]]]|S|$T|$5|U|V|W|E|$X|Y]]]]

Rails-specific

In case someone only needs to call <code>to_s</code> method to each of the values and is not using Rails 4.2 ( which includes <code>transform_values</code> method <a href="http://www.justinweiss.com/blog/2014/08/25/the-lesser-known-features-in-rails-4-dot-2/" rel="nofollow">link</a>), you can do the following:



<pre><code>original_hash = { :a =&gt; 'a', :b =&gt; BigDecimal('23.4') }
#=&gt; {:a=&gt;"a", :b=&gt;#&lt;BigDecimal:5c03a00,'0.234E2',18(18)&gt;}
JSON(original_hash.to_json)
#=&gt; {"a"=&gt;"a", "b"=&gt;"23.4"}
</code></pre>

Note: The use of 'json' library is required.

Note 2: This will turn keys into strings as well

blocks|key|3328482|text|如果知道这些值是字符串，那么可以在循环中对它们调用replace方法:这样您就可以更改值了。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3328483|Altohugh这仅限于值是字符串的情况，因此不能完全回答问题，我认为它对某些人很有用。|3328484|entityMap|0|LINK|mutability|MUTABLE|url|http://ruby-doc.org/core-2.2.3/String.html#method-i-replace^0|P|7|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]]|C|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@]|C|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|M]]]]

If you know that the values are strings, you can call the <a href="http://ruby-doc.org/core-2.2.3/String.html#method-i-replace" rel="nofollow">replace</a> method on them while in the cycle: this way you will change the value.

Altohugh this is limited to the case in which the values are strings and hence doesn't answer the question fully, I thought it can be useful to someone.

blocks|key|3328486|text|new_hash+=+old_hash.merge(old_hash)+do+%7C_key,+value,+_value%7C
+++++++++++++value.upcase
+++++++++++end

#+old_hash+=+{"a"+=>+"b",+"c"+=>+"d"}
#+new_hash+=+{"a"+=>+"B",+"c"+=>+"D"}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|3328487|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>new_hash = old_hash.merge(old_hash) do |_key, value, _value|
 value.upcase
 end

# old_hash = {"a" =&gt; "b", "c" =&gt; "d"}
# new_hash = {"a" =&gt; "B", "c" =&gt; "D"}
</code></pre>

I'd like to replace each <code>value</code> in a hash with <code>value.some_method</code>.

For example, for given a simple hash:

<pre><code>{"a" =&gt; "b", "c" =&gt; "d"}` 
</code></pre>

every value should be <code>.upcase</code>d, so it looks like:

<pre><code>{"a" =&gt; "B", "c" =&gt; "D"}
</code></pre>

I tried <code>#collect</code> and <code>#map</code> but always just get arrays back. Is there an elegant way to do this?

UPDATE 

Damn, I forgot: The hash is in an instance variable which should not be changed. I need a new hash with the changed values, but would prefer not to define that variable explicitly and then loop over the hash filling it. Something like:

<pre><code>new_hash = hash.magic{ ... }
</code></pre>

How to change Hash values?

JSON

我想用value.some_method替换散列中的每个value。例如，对于给定的简单散列：{"a" => "b", "c" => "d"}` 每个值都应该是.upcased，所以看起来像这样：{"a" => "B", "c" => "D"}我尝试过#collect和#map，但总是只能得到数组。有没有一种优雅的方法来做到这一点呢？更新该死，我忘了:哈希是在一个不应该被改变的实例变量中。我需要一

问如何更改哈希值？
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回答 12

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问如何更改哈希值？EN

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问如何更改哈希值？
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