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Adds a cheatsheet for Java fixes issue #42 #45
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3a5ce80
Adds a cheatsheet for Java fixes issue #42
Tristan-Raz 5f70b7e
Moves the cheat sheet to the appendix
Tristan-Raz b36e935
Merge branch 'master' into adding-cheat-sheet-issue42
Tristan-Raz 59186ee
Fixes merge conflicts and issue #42
Tristan-Raz 5711d75
Fixes syntax errors and explains a bit more. Still keeps one line loo…
Tristan-Raz 0e6b375
Adds code blocks, formats, and fixes issue #42
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,205 @@ | ||
| <?xml version="1.0" encoding="UTF-8"?> | ||
|
|
||
| <section xml:id="ap-java-cheatsheet" xmlns:xi="http://www.w3.org/2001/XInclude"> | ||
| <title>Java Cheat Sheet</title> | ||
| <paragraphs> | ||
| <title>Purpose of this Cheat Sheet</title> | ||
| <p> | ||
| </p> | ||
| <p> | ||
| The following is intended to be useful in better understanding Java functions coming from a Python background. | ||
| </p> | ||
| </paragraphs> | ||
| <paragraphs> | ||
| <table> | ||
| <title>Function/Method Equivalents: Python to Java</title> | ||
| <tabular> | ||
| <row header="yes"> | ||
| <cell> Python Function </cell> | ||
| <cell> Java Equivalent </cell> | ||
| <cell> Description </cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>print()</c></cell> | ||
| <cell><c>System.out.println()</c></cell> | ||
| <cell> Prints output to the console. </cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>len()</c></cell> | ||
| <cell><c>array.length</c> or <c>list.size()</c></cell> | ||
| <cell> Returns the length of an array or size of a list. </cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>range()</c></cell> | ||
| <cell><c>for (int i = 0; i < n; i++)</c></cell> | ||
| <cell> Used in loops to iterate a specific number of times. </cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>str()</c></cell> | ||
| <cell><c>String.valueOf()</c></cell> | ||
| <cell> Converts an object to a string. </cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>int()</c></cell> | ||
| <cell><c>Integer.parseInt()</c></cell> | ||
| <cell> Converts a string to an integer. </cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>float()</c></cell> | ||
| <cell><c>Float.parseFloat()</c></cell> | ||
| <cell> Converts a string to a float. </cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>list.append()</c></cell> | ||
| <cell><c>ArrayList.add()</c></cell> | ||
| <cell> Adds an element to the end of a list. </cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>list.pop()</c></cell> | ||
| <cell><c>ArrayList.remove(index)</c></cell> | ||
| <cell> Removes and assign the return value to use it.</cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>list.sort()</c></cell> | ||
| <cell><c>Collections.sort(list)</c></cell> | ||
| <cell> Sorts a list in ascending order. </cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>list.reverse()</c></cell> | ||
| <cell><c>Collections.reverse(list)</c></cell> | ||
| <cell> Reverses the order of elements in a list. </cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>dict.get()</c></cell> | ||
| <cell><c>Map.get(key)</c></cell> | ||
| <cell> Retrieves the value associated with a key in a map. </cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>dict.keys()</c></cell> | ||
| <cell><c>Map.keySet()</c></cell> | ||
| <cell> Returns a set of keys in a map. </cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>dict.values()</c></cell> | ||
| <cell><c>Map.values()</c></cell> | ||
| <cell> Returns a collection of values in a map. </cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>dict.items()</c></cell> | ||
| <cell><c>Map.entrySet()</c></cell> | ||
| <cell> Returns a set of key-value pairs in a map. </cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>input()</c></cell> | ||
| <cell><c>Scanner.nextLine()</c></cell> | ||
| <cell> Reads a line of input from the console. </cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>open()</c></cell> | ||
| <cell><c>FileReader</c>, <c>BufferedReader</c></cell> | ||
| <cell> Used to read from files. </cell> | ||
| </row> | ||
| <row> | ||
| <cell><c>enumerate()</c></cell> | ||
| <cell><c>for (int i = 0; i < list.size(); i++) { ... }</c></cell> | ||
| <cell> Used to iterate over a list with an index. </cell> | ||
| </row> | ||
| </tabular> | ||
| </table> | ||
| <table> | ||
| <title>Operator Equivalents and Usage</title> | ||
| <tabular> | ||
| <row header="yes"> | ||
| <cell> Operator Type </cell> | ||
| <cell> Operator </cell> | ||
| <cell> Description </cell> | ||
| <cell> Example </cell> | ||
| </row> | ||
| <row> | ||
| <cell> Arithmetic </cell> | ||
| <cell><c>+</c>, <c>-</c>, <c>*</c>, <c>/</c></cell> | ||
| <cell> Addition, Subtraction, Multiplication, Division </cell> | ||
| <cell><c>5 + 2</c></cell> | ||
| </row> | ||
| <row> | ||
| <cell> Arithmetic </cell> | ||
| <cell><c>/</c></cell> | ||
| <cell> Integer Division (truncates toward zero) </cell> | ||
| <cell><c>7 / 2</c> → 3 </cell> | ||
| </row> | ||
| <row> | ||
| <cell> Arithmetic </cell> | ||
| <cell><c>%</c></cell> | ||
| <cell> Modulus (remainder) </cell> | ||
| <cell><c>7 % 2</c> → 1 </cell> | ||
| </row> | ||
| <row> | ||
| <cell> Arithmetic </cell> | ||
| <cell><c>Math.pow()</c></cell> | ||
| <cell> Exponent </cell> | ||
| <cell><c>Math.pow(2, 3)</c> → 8.0 </cell> | ||
| </row> | ||
| <row> | ||
| <cell> Comparison </cell> | ||
| <cell><c>==</c>, <c>!=</c></cell> | ||
| <cell> Equal to, Not equal to (use <c>.equals()</c> for objects) </cell> | ||
| <cell><c>x == y</c></cell> | ||
| </row> | ||
| <row> | ||
| <cell> Comparison </cell> | ||
| <cell><c>></c>, <c><</c>, <c>>=</c>, <c><=</c></cell> | ||
| <cell> Greater/Less than, or equal to </cell> | ||
| <cell><c>x > 5</c></cell> | ||
| </row> | ||
| <row> | ||
| <cell> Logical </cell> | ||
| <cell><c>&&</c>, <c>||</c>, <c>!</c></cell> | ||
| <cell> Logical AND, OR, NOT </cell> | ||
| <cell><c>x > 1 && y < 10</c></cell> | ||
| </row> | ||
| <row> | ||
| <cell> Assignment </cell> | ||
| <cell><c>+=</c>, <c>-=</c>, <c>*=</c>, <c>/=</c></cell> | ||
| <cell> Adds, subtracts, multiplies, or divides and assigns </cell> | ||
| <cell><c>x += 1</c></cell> | ||
| </row> | ||
| </tabular> | ||
| </table> | ||
|
|
||
| <p> | ||
| <ul> | ||
| <li> | ||
| <p> | ||
| Ternary Operator: Provides a compact, one-line if-else statement. For instance, <c>String result = (score >= 60) ? "Pass" : "Fail";</c> is much shorter than a full if-else block. | ||
| </p> | ||
| </li> | ||
| <li> | ||
| <p> | ||
| No Chained Comparisons: Java does not support chained comparisons. Range checks must use logical operators, such as <c>if (age >= 18 && age < 65)</c>. In Python, this could be written as <c>if 18 <= age < 65:</c>. | ||
| </p> | ||
| </li> | ||
| <li> | ||
| <p> | ||
| 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. | ||
| </p> | ||
| </li> | ||
| <li> | ||
| <p> | ||
| 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>. | ||
| </p> | ||
| </li> | ||
| <li> | ||
| <p> | ||
| Short-Circuiting: The logical operators <c>&&</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 && user.isAdmin())</c>, the code will not attempt to call <c>.isAdmin()</c> if <c>user</c> is null, preventing an error. | ||
| </p> | ||
| </li> | ||
| <li> | ||
| <p> | ||
| 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 example, to generate a list of squares, instead of a multi-line loop, you can write <c>List<Integer> squares = IntStream.range(0, 10).map(i -> i * i).boxed().collect(Collectors.toList());</c>. | ||
| </p> | ||
| </li> | ||
| </ul> | ||
| </p> | ||
|
|
||
| </paragraphs> | ||
| </section> | ||
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This seems odd to include a section AFTER the backmatter. This seems like an
appendixto me and should be xi:included inside the backmatter. Therefore it should also have anappendixtag instead of asectionPreTeXt tries to help you semantically structure your book. Its worth following its lead!
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Thank you for your help! I've now made the change, converting the section to an appendix and including it inside the backmatter tag. I will make sure to follow PreTeXt's lead on structure in the future.