How I can insert a new item to an array ?
Short answer : We have a special function : AIns()
Long Answer :
AIns() function may cause some confusions when documentation not read carefully:
This function inserts a NIL value in the array named <aArray> at the <nPos>th position.
All array elements starting with the <nPos>th position will be shifted down one subscript position in the array list and the last item in the array will be removed completely.
Let’s try:
aTest := { 'One', 'Two', 'Four' }
AIns( aTest, 3 )
AEVAL( aTest, { | c1 | QQOUT( c1, '' ) } )
Result : One Two NIL: “Four” lost !
Since it’s NIL, we can assign a value to it:
aTest := { 'One', 'Two', 'Four' }
AIns( aTest, 3 )
aTest[ 3 ] := "Three"
AEVAL( aTest, { | c1 | QQOUT( c1, '' ) } )
Result : One Two Three: “Four” lost !
Before insert we can add a dummy item to end of array:
aTest := { 'One', 'Two', 'Four' }
AADD( aTest, NIL )
AIns( aTest, 3 )
aTest[ 3 ] := "Three"
AEVAL( aTest, { | c1 | QQOUT( c1, '' ) } )
Result : One Two Three Four : OK
Or we can change size of array :
aTest := { 'One', 'Two', 'Four' }
ASIZE( aTest, 4 )
AIns( aTest, 3 )
aTest[ 3 ] := "Three"
AEVAL( aTest, { | c1 | QQOUT( c1, '' ) } )
Result : One Two Three Four : OK
But wait; we have another possibility: a new Harbour function:
aTest := { 'One', 'Two', 'Four' }
HB_AIns( aTest, 3, "Three" )
AEVAL( aTest, { | c1 | QQOUT( c1, '' ) } )
Result : One Two Three: “Four” lost !
And we have a fourth parameter : Grow or not:
aTest := { 'One', 'Two', 'Four' }
HB_AIns( aTest, 3, "Three", .T. )
AEVAL( aTest, { | c1 | QQOUT( c1, '' ) } )
Result : One Two Three Four
That’s all !