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<h2>Collections, Lists, etc.</h2>

<h3>Why don't return statements work when iterating through an object?</h3>

<p>The {...} in an each statement is not a normal Java block of code, but a <em>closure</em>.  Closures are like classes/methods, so returning from one simply exits out of the closure, not the enclosing method.</p>

<h3>How do I declare and initialize a list at the same time?</h3>

<p>Syntax: </p>
<table class="wysiwyg-macro" data-macro-name="code" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e2NvZGV9&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>def x = [ "a", "b" ]
</pre></td></tr></table>

<h3>How do I declare and initialize a traditional array at the same time?</h3>

<p>or </p>
<table class="wysiwyg-macro" data-macro-name="code" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e2NvZGV9&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>String[] x = [ "a", "qrs" ] as String[]
</pre></td></tr></table>

<p>or </p>
<table class="wysiwyg-macro" data-macro-name="code" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e2NvZGV9&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>def x = [ "a", "qrs" ] as String[]
</pre></td></tr></table>

<h3>Why does <code>myMap.size</code> or <code>myMap.class</code> return null?</h3>
<p>In Groovy, maps override the dot operator to behave the same as the index[ ] operator:</p>
<table class="wysiwyg-macro" data-macro-name="code" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e2NvZGV9&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>myMap["size"]="ONE MILLION!!!";
println myMap.size        // outputs 'ONE MILLION!!!'

//use the following:
println myMap.@size       // '1'
println myMap.size()      // '1'
println myMap.getClass()  // 'class java.util.HashMap'
</pre></td></tr></table>

<h3>Why is my map returning null values?</h3>
<p>Chances are, you tried to use a variable as a key in a map literal definition.  <br />
Remember, keys are interpreted as literal strings: </p>
<table class="wysiwyg-macro" data-macro-name="code" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e2NvZGV9&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>myMap = [myVar:"one"]
assert myMap[ "myVar" ] == "one"
</pre></td></tr></table>

<p>Try this (note the parentheses around the key):</p>
<table class="wysiwyg-macro" data-macro-name="code" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e2NvZGV9&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>myMap = [(myVar):"one"]</pre></td></tr></table>