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Merge pull request #45 from Tristan-Raz/adding-cheat-sheet-issue42
Adds a cheatsheet for Java fixes issue #42
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‎source/ap-java-cheatsheet.ptx

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<?xml version="1.0" encoding="UTF-8"?>
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<section xml:id="ap-java-cheatsheet" xmlns:xi="http://www.w3.org/2001/XInclude">
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<title>Java Cheat Sheet</title>
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<paragraphs>
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<title>Purpose of this Cheat Sheet</title>
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<p>
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</p>
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<p>
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The following is intended to be useful in better understanding Java functions coming from a Python background.
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</p>
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</paragraphs>
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<paragraphs>
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<table>
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<title>Function/Method Equivalents: Python to Java</title>
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<tabular>
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<row header="yes">
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<cell> Python Function </cell>
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<cell> Java Equivalent </cell>
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<cell> Description </cell>
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</row>
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<row>
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<cell><c>print()</c></cell>
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<cell><c>System.out.println()</c></cell>
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<cell> Prints output to the console. </cell>
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</row>
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<row>
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<cell><c>len()</c></cell>
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<cell><c>array.length</c> or <c>list.size()</c></cell>
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<cell> Returns the length of an array or size of a list. </cell>
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</row>
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<row>
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<cell><c>range()</c></cell>
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<cell><c>for (int i = 0; i &lt; n; i++)</c></cell>
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<cell> Used in loops to iterate a specific number of times. </cell>
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</row>
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<row>
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<cell><c>str()</c></cell>
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<cell><c>String.valueOf()</c></cell>
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<cell> Converts an object to a string. </cell>
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</row>
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<row>
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<cell><c>int()</c></cell>
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<cell><c>Integer.parseInt()</c></cell>
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<cell> Converts a string to an integer. </cell>
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</row>
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<row>
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<cell><c>float()</c></cell>
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<cell><c>Float.parseFloat()</c></cell>
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<cell> Converts a string to a float. </cell>
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</row>
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<row>
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<cell><c>list.append()</c></cell>
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<cell><c>ArrayList.add()</c></cell>
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<cell> Adds an element to the end of a list. </cell>
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</row>
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<row>
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<cell><c>list.pop()</c></cell>
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<cell><c>ArrayList.remove(index)</c></cell>
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<cell> Removes and assign the return value to use it.</cell>
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</row>
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<row>
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<cell><c>list.sort()</c></cell>
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<cell><c>Collections.sort(list)</c></cell>
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<cell> Sorts a list in ascending order. </cell>
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</row>
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<row>
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<cell><c>list.reverse()</c></cell>
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<cell><c>Collections.reverse(list)</c></cell>
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<cell> Reverses the order of elements in a list. </cell>
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</row>
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<row>
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<cell><c>dict.get()</c></cell>
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<cell><c>Map.get(key)</c></cell>
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<cell> Retrieves the value associated with a key in a map. </cell>
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</row>
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<row>
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<cell><c>dict.keys()</c></cell>
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<cell><c>Map.keySet()</c></cell>
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<cell> Returns a set of keys in a map. </cell>
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</row>
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<row>
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<cell><c>dict.values()</c></cell>
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<cell><c>Map.values()</c></cell>
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<cell> Returns a collection of values in a map. </cell>
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</row>
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<row>
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<cell><c>dict.items()</c></cell>
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<cell><c>Map.entrySet()</c></cell>
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<cell> Returns a set of key-value pairs in a map. </cell>
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</row>
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<row>
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<cell><c>input()</c></cell>
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<cell><c>Scanner.nextLine()</c></cell>
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<cell> Reads a line of input from the console. </cell>
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</row>
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<row>
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<cell><c>open()</c></cell>
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<cell><c>FileReader</c>, <c>BufferedReader</c></cell>
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<cell> Used to read from files. </cell>
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</row>
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<row>
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<cell><c>enumerate()</c></cell>
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<cell><c>for (int i = 0; i &lt; list.size(); i++) { ... }</c></cell>
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<cell> Used to iterate over a list with an index. </cell>
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</row>
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</tabular>
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</table>
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<table>
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<title>Operator Equivalents and Usage</title>
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<tabular>
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<row header="yes">
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<cell> Operator Type </cell>
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<cell> Operator </cell>
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<cell> Description </cell>
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<cell> Example </cell>
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</row>
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<row>
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<cell> Arithmetic </cell>
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<cell><c>+</c>, <c>-</c>, <c>*</c>, <c>/</c></cell>
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<cell> Addition, Subtraction, Multiplication, Division </cell>
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<cell><c>5 + 2</c> → <c> 7 </c></cell>
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</row>
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<row>
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<cell> Arithmetic </cell>
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<cell><c>/</c></cell>
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<cell> Integer Division (truncates toward zero) </cell>
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<cell><c>7 / 2</c> → <c> 3 </c> </cell>
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</row>
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<row>
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<cell> Arithmetic </cell>
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<cell><c>%</c></cell>
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<cell> Modulus (remainder) </cell>
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<cell><c>7 % 2</c> → <c> 1 </c></cell>
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</row>
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<row>
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<cell> Arithmetic </cell>
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<cell><c>Math.pow()</c></cell>
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<cell> Exponent </cell>
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<cell><c>Math.pow(2, 3)</c> → <c> 8.0 </c></cell>
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</row>
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<row>
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<cell> Assignment </cell>
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<cell><c>+=</c>, <c>-=</c>, <c>*=</c>, <c>/=</c></cell>
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<cell> Adds, subtracts, multiplies, or divides and assigns </cell>
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<cell><c>x += 1</c> → <c>x = x + 1</c> </cell>
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</row>
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<row>
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<cell> Comparison </cell>
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<cell><c>==</c>, <c>!=</c></cell>
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<cell> Equal to, Not equal to (use <c>.equals()</c> for objects) </cell>
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<cell><c>x == y</c> → <c>True</c> or <c>False</c> </cell>
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</row>
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<row>
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<cell> Comparison </cell>
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<cell><c>&gt;</c>, <c>&lt;</c>, <c>&gt;=</c>, <c>&lt;=</c></cell>
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<cell> Greater/Less than, or equal to </cell>
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<cell><c>x &gt; 5</c> → <c>True</c> or <c>False</c> </cell>
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</row>
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<row>
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<cell> Logical </cell>
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<cell><c>&amp;&amp;</c>, <c>||</c>, <c>!</c></cell>
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<cell> Logical AND, OR, NOT </cell>
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<cell><c>x &gt; 1 &amp;&amp; y &lt; 10</c> → <c>True</c> or <c>False</c> </cell>
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</row>
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</tabular>
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</table>
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<p>
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<ul>
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<li>
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<p>
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Ternary Operator: Provides a compact, one-line if-else statement. For instance, <c>String result = (score &gt;= 60) ? "Pass" : "Fail";</c> is much shorter than a full if-else block.
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</p>
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</li>
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<li>
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<p>
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No Chained Comparisons: Java does not support chained comparisons. Range checks must use logical operators, such as <c>if (age &gt;= 18 &amp;&amp; age &lt; 65)</c>. In Python, this could be written as <c>if 18 &lt;= age &lt; 65:</c>.
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</p>
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</li>
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<li>
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<p>
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String Formatting: Java uses methods like <c>String.format()</c> or <c>System.out.printf()</c> for embedding expressions in strings, similar to Python's F-Strings. For example, <c>String message = String.format("Hello, %s!", name);</c> is cleaner than traditional string concatenation.
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</p>
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</li>
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<li>
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<p>
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No Tuple or List Unpacking: Java does not have a direct equivalent to Python's tuple and list unpacking. Assignment must be done one variable at a time, such as <c>String name = "Alice"; int age = 30;</c>.
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</p>
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</li>
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<li>
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<p>
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Short-Circuiting: The logical operators <c>&amp;&amp;</c> (AND) and <c>||</c> (OR) are efficient. They stop evaluating as soon as the outcome is known. For example, in <c>if (user != null &amp;&amp; user.isAdmin())</c>, the code will not attempt to call <c>.isAdmin()</c> if <c>user</c> is null, preventing an error.
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</p>
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</li>
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<li>
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<p>
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Streams API: Java's Stream API is the idiomatic alternative to Python's List Comprehensions. It can be used to filter, map, and reduce data in a sequence of steps. For a simpler example, to generate a basic list of numbers, instead of a multi-line loop, you can write <c>List&lt;Integer&gt; numbers = IntStream.range(0, 5).boxed().toList(); </c> This single line creates a stream of numbers from 0 to 4, prepares them for the list with the `.boxed()` method, and collects them into the final result.
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</p>
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</li>
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</ul>
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</p>
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</paragraphs>
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</section>

‎source/meta_backmatter.ptx

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<?xml version="1.0"?>
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<!-- Generated by Docutils 0.19 -->
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<backmatter xml:id="meta_backmatter">
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<backmatter xml:id="meta_backmatter" xmlns:xi="http://www.w3.org/2001/XInclude">
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<title> Appendices </title>
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<appendix>
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<title>Java Cheat Sheet</title>
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<p>This is a quick reference guide for Java syntax and concepts.</p>
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<xi:include href="ap-java-cheatsheet.ptx" />
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</appendix>
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<appendix xml:id="backmatter_appendix">
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<title>Shameless Plug</title>
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