[RegExp] Замена по условию

StringInStr

$sText = 'D,1230'
If StringRegExp($sText, '^D,(\d{3})') Then
  $sText = StringRegExpReplace($sText, '^(D),(\d{3})0', 'Day,$2')
Else
  $sText = StringRegExpReplace($sText, '^(\d{1,2}),(\d{3})0', '$1,$2')
EndIf

ConsoleWrite(StringRegExpReplace('D,1230', 'D,(\d+)', 'Day,$1'))
;или так
ConsoleWrite(StringRegExpReplace('D,1230', 'D,(?=\d+)', 'Day,$1'))

ConsoleWrite(StringRegExpReplace('D,1230', 'D,(?=\d+)', 'Day,$1')) --> '5,1230'

StringRegExpReplace

$sData = ''
$aData = StringRegExp('D,1230 5,1230  C,1230 7,1230  ', '(D|\d)?,(?(1)(\d{0,3})0|%#%)', 3)

For $i = 1 To UBound($aData)-1 Step 2
	If Mod($i, 2) And $aData[$i-1] = 'D' Then
		$aData[$i-1] = 'Day'
	EndIf
	$sData &= StringFormat('%s,%s\n', $aData[$i-1], $aData[$i])
Next
ConsoleWrite($sData)