Replace element at index X in a list?

[El_Pablo]

Hi,

Is there a way to replace an element in a list by using it's index?

Let say a function such as ReplaceAtIndex(list; index; theNewValue)?

If not how would you work around this problem?

I want to replace numerical values in a list that contain bins to create a column graph.

[Ocean West]

you mean a return separated list?

Cat

Dog

Mouse

you want to replace dog at value position 2 with Horse?

[Ocean West]

try

http://www.briandunning.com/cf/319

[El_Pablo]

Thanx!

It's not exactly what I was looking for, but I guest I could modify this function for my purpose.

To answer the first post, sort of, but the list could contain twice the word dog.

Cat

Dog

Horse

Fish

Dog

I want to replace the value at index 2 for snake.

ReplaceAtIndex ($myList; 2; "snake")

[comment]

Try something like:

LeftValues ( listOfValues ; index - 1 )

&

replaceValue & ¶

&

RightValues (  listOfValues ; ValueCount ( listOfValues ) - index )

Note:

index ≤ 0 or index > ValueCount ( listOfValues ) will APPEND the new value at the beginning/end of the list.

[El_Pablo]

Voilà!

The only bug I'm trying to figure out is if the first value is negative, the minus sign is removed.

/*

--------------------------------------------------------------------------------

Returns a list with value 'value' replacing the value at index 'index'



Syntax: InsertValue ( valueList ; value ; index )



In: valueList - the return delimited list to search

      value - the stringvalue to insert

      index - the position (1-...) where the new value should go

                  If left empty or an integer value greater than the

                  total size of the list, the new value will be added

                  at the very end of the list. If <= 1 the value will

                  added at the beginning of the list.



Return type: Text (a list with leading and trailing returns removed)



ReplaceAtIndex ( "Lemieux¶Gretzky¶Robitaille" ; "Messier" ; 2 )   --> "Lemieux¶Messier¶Robitaille"



Nicolas Bourré

Based on Theo Ros script

-------------------------------------------------------------------------------- */



Let ( [ value = LeftWords( value;  999999999 ) ;

           list = LeftWords ( valueList; 999999999 ) ;

           totalvalues = ValueCount ( list ) ] ;

  Case ( totalvalues = 0 or IsEmpty ( index ) or index > totalvalues; value ;

     index < 2 ; value & "¶" & MiddleValues(list; index + 1; 999999999);

    LeftWords ( LeftValues ( list ; index - 1 ) & value & "¶" & 

                        MiddleValues ( list ; index + 1 ; 999999999 ) ; 999999999 )

  )

)

[comment]

Not in MY calculation, surely?

[bruceR]

I don't like the 99999 thing.

I'd suggest this.

// SetValue ( ListOfValues; replaceValue; index)

Let( [

LVC = ValueCount( ListOfValues);

Diff = LVC - Index ];

LeftValues ( listOfValues ; index - 1 )

&

Case( Diff > 0;

LeftValues( replaceValue; 1) & RightValues ( listOfValues ; Diff - 1 ) & GetValue( ListOfValues; LVC) ;

GetValue( ReplaceValue; 1)

)

)

[El_Pablo]

Yeah I don't like it either but I didn't had time to retouch the calculation.

Thanx for the tip.

[bruceR]

Updated, there are a few problems with the original.

Here, if you use index of 0, item is appended to top of list, if index > list value count, item is appended to end of list.

If you use negative values, e.g. -1 or -2, item is positioned counting back from end of list.

// SetValue ( ListOfValues; replaceValue; index)

Let( [

LVC = ValueCount( ListOfValues);

Index = Case( Index > -1 ; index; Abs( Index) > LVC ; 0; LVC + 1 + index );

Diff = LVC - Index ];

LeftValues ( listOfValues ; index - 1 )

&

Case( Diff > 0;

LeftValues( replaceValue; 1) & MiddleValues ( listOfValues ; Index + 1 ; Diff - 1 ) & GetValue( ListOfValues; LVC) ;

GetValue( ReplaceValue; 1)

)

)

Edited October 22, 2008 by Guest

[El_Pablo]

Nice!

You should add the function to the custom function section.