"FixedArray" (Data Structure)

"FixedArray"

represents an array of fixed length where the elements are general expressions.

Details

A fixed-length array is useful for efficient element extraction and updating:

	CreateDataStructure[ "FixedArray",n]	create a new "FixedArray" with n elements
	CreateDataStructure[ "FixedArray",x,n]	create a new "FixedArray" of length n initialized to x
	CreateDataStructure[ "FixedArray",elems]	create a new "FixedArray" containing elems
	Typed[x,"FixedArray"]	give x the type "FixedArray"

For a data structure of type "FixedArray", the following operations can be used:

ds["Copy"]	return a copy of ds	time: O(n)
ds["Elements"]	return a list of the elements of ds	time: O(n)
ds["EmptyQ"]	True, if ds has no elements	time: O(1)
ds["Fold",fun,init]	apply fun to the elements of ds, starting with init, accumulating a result	time: O(n)
ds["Length"]	number of elements stored in ds	time: O(1)
ds["Part",i]	give the i part of ds	time: O(1)
ds["SetPart",i,elem]	update the i part of ds	time: O(1)
ds["SwapPart",i,j]	swap the i and j parts of ds	time: O(1)
ds["Visualization"]	return a visualization of ds	time: O(n)

The following functions are also supported:

	ds_i===ds_j	True, if ds_i equals ds_j
	ds["Part",i]=val	set i element of ds to val
	FullForm[ds]	full form of ds
	Information[ds]	information about ds
	InputForm[ds]	input form of ds
	Normal[ds]	convert ds to a normal expression

Examples

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Basic Examples (3)

A new "FixedArray" can be created with CreateDataStructure:

Return the length:

Return an expression version of ds. The elements are initialized to Null:

Change an element:

The element has updated:

The expression version of ds:

It is fast to update elements:

A visualization of the data structure can be generated:

Sum all the elements:

An initial value can be given:

Scope (1)

Information (1)

A new "FixedArray" can be created with CreateDataStructure:

Information about the data structure ds:

Properties & Relations (1)

"DynamicArray" (1)

Many algorithms that work for "DynamicArray" also work for "FixedArray".

Possible Issues (2)

The number of elements of the array needs to be specified as a positive integer:

You cannot set parts of the array that do not exist:

Interactive Examples (1)

Compute and store individual plots in a data structure and use Manipulate to interactively display them:

Neat Examples (2)

Fibonacci (1)

Compute the first 16 elements of the Fibonacci sequence:

Set the first two elements to 1, then compute the remaining elements:

Display the result:

Histogram (1)

A function that computes a histogram of the different color values of an image:

Run the function on the pixels of an image: