Arrays: Difference between revisions
add RPL
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=={{header|RPL}}==
Arrays have a predefined size and can only contain floating point numbers.
They can be created either by enumerating their elements one by one or by creating an array with the same value everywhere:
[ 1 2 3 4 5 ]
{ 5 } -1 CON <span style="color:grey">@ create the array [ -1 -1 -1 -1 -1 ]</span>
To assign a value, you can use either <code>PUT</code> or <code>PUTI</code>. <code>PUT</code> returns only the updated array - other input arguments are gone - whilst <code>PUTI</code> leaves in stack the index, incremented by one : you can then easily assign another value to the following position.
[ 1 2 3 4 5 ] 3 10 PUT
returns:
1: [ 1 2 10 4 5 ]
but
[ 1 2 3 4 5 ] 3 10 PUTI
returns:
2: [ 1 2 10 4 5 ]
1: 4
Similarly, you can use <code>GET</code> or <code>GETI</code> to retrieve an element.
[ 10 20 30 40 50 ] 3 GET
returns:
1: 30
but
[ 10 20 30 40 50 ] 3 GETI
returns:
3: [ 10 20 30 40 50 ]
2: 4
1: 30
Another useful data structure in RPL is the list, which is very similar in use to arrays: <code>PUT</code>, <code>PUTI</code>, <code>GET</code> and <code>GETI</code> give the same results. Lists can contain any kind of objects, including lists. Beside direct assignment through <code>PUT</code>, it is also possible to append an element at the beginning or the end of the list with the <code>+</code> operator.
In recent RPL versions, several functions such as <code>SORT</code> can be applied only to lists, which make this data structure very versatile. The only drawback is the necessity to create a list element by element
by direct enumeration:
{ 1 2 3 4 5 }
by concatenation:
{ 1 2 3 } { 4 5 } +
or through a loop:
{ } 1 5 '''FOR''' j j + '''NEXT'''
=={{header|Ruby}}==
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