Students
This is a comparison of the syntax of some popular programming languages, including Scala which we will be using on 5CS004. Where you see the word "TODO", please collaborate to fill in the blank parts of the tables. We will be adding to this page as the module progresses.
Useful language references
Basics
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PHP
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Java
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Scala
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Python
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| Single line comment
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// comment
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// comment
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// comment
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# comment
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| Multi-line comment
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/* comment */
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/* comment */
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/* comment */
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Doesn't have multi-line comments.
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| Null object
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NULL
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null
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TODO
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None
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| Arithmetic operators
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+,-,*,/,%,*
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+,-,*,/,%,*
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+,-,*,/,%,*
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+,-,*,/,%,*
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| True and false
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TRUE, FALSE
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true, false
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TODO
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True, False
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| Boolean operators
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&&, ||, !
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&&, ||, !
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TODO
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and, or, not
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| Relational operators
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<, >, <=, >=, ==, !=
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<, >, <=, >=, ==, !=
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<, >, <=, >=, ==, !=
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<, >, <=, >=, ==, !=
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Input / output
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PHP
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Java
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Scala
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Python
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| Print to console
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echo("hello");
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System.out.println("Hello");
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TODO
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print "Hello"
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| Read from keyboard
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readline("")
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BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
String kbd = in.readLine();
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val kbd = readLine()
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kbd = raw_input() # kbd is a string
kbd = input() # kdb may be some other type
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Selection
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PHP
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Java
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Scala
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Python
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| if/else
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if ($a==$b) {
echo("same");
} else {
echo("different");
}
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if (a==b) {
System.out.println("same");
} else {
System.out.println("different");
}
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TODO
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if a==b:
print 'same'
else:
print 'different'
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| else-if
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if ($a<0) {
echo("negative");
} elseif ($a==0) {
echo("zero");
} else {
echo("positive");
}
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TODO
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TODO
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if a<0:
print 'negative'
elif a==0:
print 'zero'
else:
print 'positive'
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| switch
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switch ($i) {
case 0:
echo "i equals 0";
break;
case 1:
echo "i equals 1";
break;
case 2:
echo "i equals 2";
break;
}
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switch ($i) {
case 0:
System.out.println("i equals 0");
break;
case 1:
System.out.println("i equals 1");
break;
case 2:
System.out.println("i equals 2");
break;
}
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TODO
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No equivalent. Use "if" instead.
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Iteration
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PHP
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Java
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Scala
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Python
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| for
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for ($i=0; $i<10; $i++) {
echo($i);
}
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TODO
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for(int i=0; i<10; i++) {
System.out.println(i);
}
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No equivalent
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| foreach
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$a = array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
foreach ($a as $v) {
echo $v;
}
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No equivalent.
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TODO
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for i in range(10):
print i
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| while
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$i=0;
while ($i<10) {
echo $i;
$i++;
}
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int i=0;
while(i<10) {
System.out.println(i);
i++'
}
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TODO
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i=0
while i<10:
print i
i += 1
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Functions
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PHP
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Java
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Scala
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Python
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| Defining functions
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function print_msg($msg) {
echo $msg;
}
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No equivalent. Use methods.
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TODO
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def print_msg(msg):
print msg
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Compound types (arrays, lists, etc)
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PHP
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Java
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Scala
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Python
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| Fixed length array
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TODO
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TODO
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TODO
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TODO
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| Mutable array
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TODO
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TODO
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TODO
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TODO
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| Associative arrays / hashes
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TODO
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TODO
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TODO
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TODO
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Exception handling
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PHP
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Java
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Scala
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Python
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| Raise an exception
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throw new Exception("Division by zero");
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throw new ClassNotFoundException();
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TODO
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raise ValueError()
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| Handle / catch an exception
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TODO
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TODO
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TODO
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TODO
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Dealing with types
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PHP
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Java
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Scala
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Python
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| Convert object to different type
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TODO
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TODO
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TODO
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TODO
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Classes, objects, methods, etc
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PHP
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Java
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Scala
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Python
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| Root object
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TODO
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java.lang.Object
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TODO
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object
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| Create an object
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TODO
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TODO
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TODO
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TODO
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| Call methods
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TODO
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TODO
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TODO
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TODO
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| Create and update instance attribute
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TODO
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TODO
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TODO
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TODO
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| Create and update class attribute
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TODO
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TODO
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TODO
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TODO
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| Create subclass
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TODO
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TODO
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TODO
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TODO
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