Arrays [examples]

Copy records to an array of objects
COPY TO ARRAYOFOBJECTS
open database southwind
use shippers
copy to arrayofobjects aShipObjects for shipperid < 3 ? aShipObjects   Array (refcnt=1) (     [1] = Dynarray         (             [shipperid] => 1
            [companyname] => Speedy Express                          
            [phone] => (503) 555-9831          
        )
    [2] = Dynarray
        (
            [shipperid] => 2
            [companyname] => United Package                          
            [phone] => (503) 555-3199          
        )
)

https://www.lianja.com/doc/index.php/COPY_TO_ARRAYOFOBJECTS


Copy current table to an array
COPY TO ARRAY
declare orders[10000,10]
use suppliers
copy to array orders for ord_date < date()

https://www.lianja.com/doc/index.php/COPY_TO_ARRAY


Append records to current table from an array
APPEND FROM ARRAY
use suppliers
declare cust[reccount(), fcount()]
copy to array cust
copy structure to customer
use customer
append from array cust for also_cust = .T.

https://www.lianja.com/doc/index.php/APPEND_FROM_ARRAY


Declare an array

DECLARE
DIMENSION

Dynamic arrays are declared without specifying a size. Elements are added using arrayname.element syntax.

aDynarray.name = [Lianja Inc]
aDynarray.email = [sales@lianja.com]

They can then be referenced by element number or by element name.

? aDynarray.name
Lianja Inc
? aDynarray[2]
sales@lianja.com

Notes: The brackets shown for this command do not indicate optional expressions but are a necessary part of the syntax. Arrays can also be declared using any of the scoping commands: LOCAL, PRIVATE and PUBLIC.

// Declare one-dimensional array of 4000 elements
declare aTable[4000]
// Assign 0 to all elements
aTable = 0
// Insert individual element values into array
aTable[1] = 10
aTable[2] = "Hello"
aTable[3] = "World"
aTable[4] = date()
// Print value of element 2
? aTable[2]
Hello
 
// Another example
declare twodim[3,3]
twodim[2,3] = "hello world"
? twodim[6]
hello world
 
// Another example
use payroll
declare aPayroll[reccount(), fcount()]
copy to array aPayroll for city = "LONDON"
 
// Dynamic array
declare aDynarray[]
aDynarray.name = [Lianja Inc]
? aDynarray.name
Lianja Inc
? aDynarray[1]
Lianja Inc

https://www.lianja.com/doc/index.php/DECLARE


Create a dynamic array

ARRAY

customer = array("custname" => "A Buyer Ltd.", ;
  "currentorder" => array("ord_id" => "00001", "ord_date" => date(),"ord_total" => 1599,;
  "orderitems" =>  array("10 reams A4 paper","500 business cards",;
                         "500 black ballpoint pens")))
display memory
 
Memory Variables:
------------------------
CUSTOMER                         Dynamic array (refptr ARRAY, refcnt 1)
.CUSTNAME                          Character 'A Buyer Ltd.'
.CURRENTORDER                     Dynamic array (refptr ARRAY, refcnt 0)
 .ORD_ID                            Character '00001'
 .ORD_DATE                          Date 11/04/2009
 .ORD_TOTAL                         Numeric 1599  (1599.000000000)
 .ORDERITEMS                       Dynamic array (refptr ARRAY, refcnt 0)
  .00000001                          Character '10 reams A4 paper'
  .00000002                          Character '500 business cards'
  .00000003                          Character '500 black ballpoint pens'
 
Total of 10 variables defined and 784 bytes used.

https://www.lianja.com/doc/index.php/ARRAY()


Add a new element to the end of an array
AADD
declare array1[3]
array1 = "test"
? alen(array1)
         3
aadd(array1,"newtest")
? array1[4]
newtest

https://www.lianja.com/doc/index.php/AADD()


Calculate the average of element values in an array
AAVERAGE
use payroll
declare number[reccount(),1]
copy to array number fields pay_value
? aaverage(number)
   1741.01

https://www.lianja.com/doc/index.php/AAVERAGE()


Copy elements from one array to another
ACOPY
declare overview[4000]
declare north[2000]
// Copy first 2000 elements from source array
// starting from position 1 in the target array
acopy(north,overview,1,2000,1)
declare south[1500]
// Copy first 1500 elements from source array
// starting from position 2001 in the target array
acopy(south,overview,1,1500,2001)

https://www.lianja.com/doc/index.php/ACOPY()


Delete an element from an array
ADEL
element_no = ascan(flist,"New information")
// If element exists
if m.element_no > 0
    adel(flist,m.element_no)
endif
 
// Two-dimensional array Examples:
 
// Row
open database southwind
use shippers
copy to array arr1
? arr1
// Delete row 2
adel(arr1,2)
? arr1
close data
 
// Results:
Array (refcnt=1)
(
    [1,1] = 1
    [1,2] = Speedy Express                          
    [1,3] = (503) 555-9831          
    [2,1] = 2
    [2,2] = United Package                          
    [2,3] = (503) 555-3199          
    [3,1] = 3
    [3,2] = Federal Shipping                        
    [3,3] = (503) 555-9931          
)
 
Array (refcnt=1)
(
    [1,1] = 1
    [1,2] = Speedy Express                          
    [1,3] = (503) 555-9831          
    [2,1] = 3
    [2,2] = Federal Shipping                        
    [2,3] = (503) 555-9931          
    [3,1] = False
    [3,2] = False
    [3,3] = False
)
 
// Column
open database southwind
use shippers
copy to array arr1
? arr1
// Delete column 2
adel(arr1,2,2)
? arr1
close data
 
// Results:
Array (refcnt=1)
(
    [1,1] = 1
    [1,2] = Speedy Express                          
    [1,3] = (503) 555-9831          
    [2,1] = 2
    [2,2] = United Package                          
    [2,3] = (503) 555-3199          
    [3,1] = 3
    [3,2] = Federal Shipping                        
    [3,3] = (503) 555-9931          
)
 
Array (refcnt=1)
(
    [1,1] = 1
    [1,2] = (503) 555-9831          
    [1,3] = False
    [2,1] = 2
    [2,2] = (503) 555-3199          
    [2,3] = False
    [3,1] = 3
    [3,2] = (503) 555-9931          
    [3,3] = False
)

https://www.lianja.com/doc/index.php/ADEL()


Search an array for an expression
ASCAN
close data
open database southwind
 
use employees
copy to array names
 
eExpression = "Rob"
nStartElement = 5
nElementsSearched = 104
nSearchColumn = 0
 
element_no=ascan(names, eExpression, nStartElement, nElementsSearched)
if element_no > 0
    ? names[element_no]
    ? element_no
else
	? "Not found"
endif
 
// Exact on
element_no=ascan(names, eExpression, nStartElement, nElementsSearched, nSearchColumn, 6)
if element_no > 0
    ? names[element_no]
    ? element_no
else
	? "Not found"
endif
 
nStartRow = 3
nRowsSearched = 6
nSearchColumn = 3
 
element_no=ascan(names, eExpression, nStartRow, nRowsSearched, nSearchColumn)
if element_no > 0
    ? names[element_no]
    ? element_no
else
	? "Not found"
endif
 
// Return row number, exact off
row_no=ascan(names, eExpression, nStartRow, nRowsSearched, nSearchColumn, 10)
if row_no > 0
    ? names[row_no, nSearchColumn]
    ? row_no
else
	? "Not found"
endif
 
// Return row number, exact on
row_no=ascan(names, eExpression, nStartRow, nRowsSearched, nSearchColumn, 14)
if row_no > 0
    ? names[row_no, nSearchColumn]
    ? row_no
else
	? "Not found"
endif

https://www.lianja.com/doc/index.php/ASCAN()


Return the number of an array element from the element subscripts
AELEMENT
declare test[4,4]
? aelement(test, 3,2)
        10

https://www.lianja.com/doc/index.php/AELEMENT()


Fill a defined section of an array with an expression
AFILL
declare matrix[100]
afill(matrix,"good",51,100)
? matrix[45]
.F.
? matrix[75]
good
? afill(matrix,"bad",1,50)
.T.
? matrix[45]
bad

https://www.lianja.com/doc/index.php/AFILL()


Insert an element into an array
AINS
declare table[10]
ains(table, 3, "hello world")
// Another Example
declare flist[5]
...
if ascan(flist, "new information") = 0
    ains(flist,1,"new information")
endif
 
// Two-dimensional array
open database southwind
use shippers
copy to array arr1
? arr1
ains(arr1,1)
? arr1
close data
 
// Results
Array (refcnt=1)
(
    [1,1] = 1
    [1,2] = Speedy Express                          
    [1,3] = (503) 555-9831          
    [2,1] = 2
    [2,2] = United Package                          
    [2,3] = (503) 555-3199          
    [3,1] = 3
    [3,2] = Federal Shipping                        
    [3,3] = (503) 555-9931          
)
 
Array (refcnt=1)
(
    [1,1] = False
    [1,2] = False
    [1,3] = False
    [2,1] = 1
    [2,2] = Speedy Express                          
    [2,3] = (503) 555-9831          
    [3,1] = 2
    [3,2] = United Package                          
    [3,3] = (503) 555-3199          
)

https://www.lianja.com/doc/index.php/AINS()


Return the number of elements, rows or columns in an array
ALEN
declare aNames[10,12]
? alen(aNames)
       120
? alen(aNames,0)
       120
? alen(aNames,1)
        10
? alen(aNames,2)
        12

https://www.lianja.com/doc/index.php/ALEN()


Return the highest element value in an array
AMAX
use payroll
declare number[reccount(),1]
copy to array number fields total
? amax(number)
   8165.19

https://www.lianja.com/doc/index.php/AMAX()


Return the lowest element value in an array
AMIN
use payroll
declare number[reccount(),1]
copy to array number fields total
? amin(number)
     16.23

https://www.lianja.com/doc/index.php/AMIN()


Resize an array
ASIZE
declare array1[100]
? alen(array1)
       100
asize(array1,200)
? alen(array1)
       200
 
declare array2[100,5]
? alen(array2)
       500
? alen(array2,1)
       100
asize(array2, alen(array2,1)+1)
? alen(array2)
       505
? alen(array2,1)
       101

https://www.lianja.com/doc/index.php/ASIZE()


Sort the elements of a specified array
ASORT
use accounts
declare names[reccount(),1]
copy to array names fields company
asort(names)

https://www.lianja.com/doc/index.php/ASORT()


Fill an array with character strings that are separated with a specified character
ASTORE
declare aNums[10]
? alen(aNums)
        10
nelements = ASTORE(aNums, "one, two, three", ",")
? nelements
         3
? alen(aNums)
         3
// Another Example
menu fields select "+"
declare aMenu[512]
nelements = astore(aMenu, menuitem(), "+")

https://www.lianja.com/doc/index.php/ASTORE()


Return an array as a character string, with the elements separated by a comma or specified character
ASTRING
menu fields select "+"
declare aMenu[512]
nelements = astore(aMenu, menuitem(), "+")
backtostring = astring(aMenu, "+")

https://www.lianja.com/doc/index.php/ASTRING()


Return the row or column number of an array element from the element number
ASUBSCRIPT
use state.rdb
private aRECORDS[50,fcount()]
copy to array aRECORDS
nELEM = ascan(aRECORDS,'California')
? asubscript(aRECORDS,nELEM,1)
         6

https://www.lianja.com/doc/index.php/ASUBSCRIPT()


Calculate the sum of element values in an array
ASUM
use payroll
declare aNumber[reccount(),1]
copy to array aNumber fields pay_amount
? asum(aNumber)
 127641.73

https://www.lianja.com/doc/index.php/ASUM()


Return the value of a dynamic array element or an alternative value if the element does not exist
GETMEMBER
tab = array("day" => "Monday", "month" => "May")
// Return "2014" if no 'year' element exists
? getmember("tab","year","2014")

https://www.lianja.com/doc/index.php/GETMEMBER()


Search an array for an expression
IN_ARRAY
open database southwind
use example
declare names[reccount(),1]
copy to array names fields start_date
valid_date = in_array({02/09/2000}, names)

https://www.lianja.com/doc/index.php/IN_ARRAY()


Check whether an expression is the name of an array
IS_ARRAY
open database southwind
select * from example into array afixed
? is_array(afixed)
.T.
select * from example into object adynamic
? is_array(adynamic)
.T.

https://www.lianja.com/doc/index.php/IS_ARRAY()


Fill an array with character strings that are separated with a newline or other specified parsing string
ALINES
// ali.prg - 4 lines
cVar=filetostr("ali.prg")
nVar = alines(aVar, cVar)
echo "Program has " + ltrim(str(nVar)) + " lines\n"
 
 
// Another Example
declare aNums[10]
nelements = alines(aNums, "one, two, three", 0, ",")

https://www.lianja.com/doc/index.php/ALINES()


Return a string from the elements of an array
IMPLODE
menu fields select "+"
aMenu = explode("+", menuitem())
backtostring = implode("+", aMenu)

https://www.lianja.com/doc/index.php/IMPLODE()


Separate a string into the elements of an array
EXPLODE

 

menu fields select "+"
aMenu = explode("+", menuitem())
backtostring = implode("+", aMenu)

https://www.lianja.com/doc/index.php/EXPLODE()


Static Arrays

A static array is an ordered list of elements (variables) that is of a fixed size (number of elements). You declare a static array by specifying the number of elements when you declare a variable.

private tab[ 20 ]    // declare a static array of 20 elements all initialized to False
 
// iterate through the array (note the use of the alen( ) function to find the length of the array
for i=1 to alen( tab )
    // change each array element to hold a numeric value
    tab[ i ] = i
endfor

You can initialize a static array with one statement.

// declare the array and init all elements to false
declare tab[10, 10]
 
// init all elements to zero
tab = 0

You can create and initialize static arrays using static array initializers.

// simple one dimensional array with 2 elements
private tab = { "Hello", "world" }
 
// two-dimensional array of two rows with three columns in each row
private tab2 = { { "Hello", 10, date() }, { "world", 20, date()+1 } }
 
// create an array on the fly
mytab = { 10, 20, 30, 40, 50, 60 }

You can view the contents of a static array using the echo or ? commands.

? tab

Associative Arrays

An associative array (also known as a dynamic array) is a collection of key/value pairs where the key can be used to retrieve the value. Associative arrays are dynamic, meaning that elements can be added and removed dynamically. The key identifiers follow the standard naming rules (see naming under Simple Variables above).

private tab[]    // note the use of [] to denote a dynamic array
 
tab["name"] = "bill"
tab["age"] = 25
tab["dob"] = date()

Associative arrays can be created and initialized in one statement using the array( ) function.

tab = array("name" => "bill", "age" => 25, ""dob" => date())

You can view the contents of an associative array using the echo or ? commands.

? tab

https://www.lianja.com/doc/index.php/A_Recital_Primer


Static Arrays

A static array is an ordered list of elements (variables) that is of a fixed size (number of elements). You declare a static array by specifying the number of elements when you declare a variable.

private tab[ 20 ]    // declare a static array of 20 elements all initialized to False
 
// iterate through the array (note the use of the alen( ) function to find the length of the array
for i=1 to alen( tab )
    // change each array element to hold a numeric value
    tab[ i ] = i
endfor

You can initialize a static array with one statement.

// declare the array and init all elements to false
declare tab[10, 10]
 
// init all elements to zero
tab = 0

You can create and initialize static arrays using static array initializers.

// simple one dimensional array with 2 elements
private tab = { "Hello", "world" }
 
// two-dimensional array of two rows with three columns in each row
private tab2 = { { "Hello", 10, date() }, { "world", 20, date()+1 } }
 
// create an array on the fly
mytab = { 10, 20, 30, 40, 50, 60 }

You can view the contents of a static array using the echo or ? commands.

? tab

Associative Arrays

An associative array (also known as a dynamic array) is a collection of key/value pairs where the key can be used to retrieve the value. Associative arrays are dynamic, meaning that elements can be added and removed dynamically. The key identifiers follow the standard naming rules (see naming under Simple Variables above).

private tab[]    // note the use of [] to denote a dynamic array
 
tab["name"] = "bill"
tab["age"] = 25
tab["dob"] = date()

Associative arrays can be created and initialized in one statement using the array( ) function.

tab = array("name" => "bill", "age" => 25, ""dob" => date())

You can view the contents of an associative array using the echo or ? commands.

? tab

https://www.lianja.com/doc/index.php/A_Lianja_Primer


Static Arrays

A static array is an ordered list of elements (variables) that is of a fixed size (number of elements). You declare a static array by specifying the number of elements when you declare a variable.

private tab[ 20 ]    // declare a static array of 20 elements all initialized to False
 
// iterate through the array (note the use of the alen( ) function to find the length of the array
for i=1 to alen( tab )
    // change each array element to hold a numeric value
    tab[ i ] = i
endfor

You can initialize a static array with one statement.

// declare the array and init all elements to false
declare tab[10, 10]
 
// or
dimension tab(10, 10)
 
// init all elements to zero
tab = 0

You can create and initialize static arrays using static array initializers.

// simple one dimensional array with 2 elements
private tab = { "Hello", "world" }
 
// two-dimensional array of two rows with three columns in each row
private tab2 = { { "Hello", 10, date() ], { "world", 20, date()+1 } }
 
// create an array on the fly
mytab = { 10, 20, 30, 40, 50, 60 }

You can view the contents of a static array using the echo or ? commands.

? tab

Accessing Elements in a Static Array

Elements in a static array are accessed using the element number, or the element subscripts in the case of two-dimensional arrays. Array element numbers and subscripts start from 1 and are specified in square or round brackets after the array name. Row and column subscripts are separated by a comma: [row,column].

? array1[3]
? array2[2,4]
? array3(5,2)

Associative Arrays

An associative array (also known as a dynamic array) is a collection of key/value pairs where the key can be used to retrieve the value. The key names conform to the standard identifier naming rules: an identifier must begin with a letter (A-Z, a-z) or an underscore (-), followed by any combination of letters, digits or underscores. The identifier can be of any length, but only the first 32 characters are significant, so these must be unique.

Associative arrays are dynamic, meaning that elements can be added and removed dynamically.

private tab[]    // note the use of [] to denote a dynamic array
 
tab["name"] = "bill"
tab["age"] = 25
tab["doj"] = date()
 
// Alternative syntax
private tab[]
 
tab.name = "bill"
tab.age = 25
tab.doj = date()

Associative arrays can be created and initialized in one statement using the array( ) function.

tab = array("name" => "bill", "age" => 25, ""doj" => date())

You can view the contents of an associative array using the echo or ? commands.

? tab

Accessing Elements in an Associative Array

Like static arrays, associative arrays can also be accessed via their element number in square brakets:

private tab[]
tab.name = "bill"
tab.age = 25
tab.doj = date()
 
? tab[2]
        25

However, they are most commonly accessed via their key:

? tab.age
        25

When setting the element value, the key must be used.

tab["age"] = 26

Looping Through Arrays

// static array
numbers = array(1,2,3,4,5,6,7,8,9,10)
foreach numbers as elem
    ? elem * elem
endfor
 
// associative array
private myarray = array("Name" => "Lianja", "Description" => "database")
foreach myarray as key => value
    echo "key=" + key + " value=" + value + "\n"
endfor

Passing Arrays as Function Arguments

Both static and dynamic arrays are passed to functions by reference, allowing the original of the array to be updated by the called function.

function func1
    parameter p1
    p1.age = 27
return .t.
 
private tab[]
tab.name = "Bill"
tab.age = 25
func1(tab)
echo tab.age, "\n"
       27

 https://www.lianja.com/doc/index.php/Lianja_Arrays


Advertisements