How do I Find a non numeric value in a string?

mickbarrsmickbarrs Member Posts: 17
I'm trying to find the position of the first value that is not a numeric value within a string.

pTxtNumber is passed in and could be 10-15672 for example. So I want to return position 3 because this is the first non numeric character. Then I want to chop of the string up to and including this character so that I am left with 15672.

This code i initially did checks for where the numeric value begins but now i want to do the opposit.

FOR i := 1 TO STRLEN(pTxtNumber) DO BEGIN
IF Pos = 0 THEN
Pos := i;

Any help would be greatly appreciated.




  • HalMdyHalMdy Member Posts: 429
    In place of

    IF FORMAT(pTxtNumber) IN THEN


    IF NOT (FORMAT(pTxtNumber) IN ) THEN

    I think it could work ...
  • mickbarrsmickbarrs Member Posts: 17
    'The prefix operator cannot be used on text'. I also tried:


    and this did not work either.

    I suppose i could enter into a substring 'abcdefg-!"£$%^&*' etc and then check in my string to see if it contains any of the characters in the substring but i thought there might be a more efficient way of saying find the first non-numeric character.

    Any ideas?
  • krikikriki Member, Moderator Posts: 8,914
    txtString := '10-15672';
    txtNoNumbers := DELCHR(txtString,'=','1234567890'); // remain only non-number chars and the first char in the resulting string will be the first non-numeric char in the original string
    WHILE txtNoNumber <> '' DO BEGIN
      // take the first char of "txtNoNumber" (there can be multiple non-numeric chars)
      // and give me the position where it is in "txtString"
      intNoNumber := STRPOS(txtString,COPYSTR(txtNoNumber,1,1));
      // "txtString" now starts AFTER the first non-numeric char 
      txtString := COPYSTR(txtString,intNoNumber + 1);
      // lets check if there are other non-numeric chars
      txtNoNumbers := DELCHR(txtString,'=','1234567890');
    MESSAGE('The string "txtString" (=%1) doesn''t contain non-numeric chars',txtString);
    Regards,Alain Krikilion
    No PM,please use the forum. || May the <SOLVED>-attribute be in your title!
    NAV TechDays 2020: 19 & 20 November 2020, Antwerp (Belgium)
  • DenSterDenSter Member Posts: 8,214
    If the numbers are always separated by a dash then you could do:
    TargetString := DELCHR(SourceString,'=','-');
    if there are more saparation characters, (like . or ,) you could do:
    TargetString := DELCHR(SourceString,'=','-.,');
    if you want to remove letters you do:
    TargetString := DELCHR(SourceString,'=','abcdefghijklmnopqrstuvwxyz');

    <edit>so that still doesn't give you the position of the first non numeric character..... let me think about that</edit>
  • DenSterDenSter Member Posts: 8,214
    SourceString - Text30
    TargetString - Text30
    IFoundIt - boolean
    MyPos - Integer
    MyPos := 0;
    IFoundIt := FALSE;
    SourceString := '123-456';
      MyPos += 1;
      IF DELCHR(COPYSTR(SourceString,MyPos,1),'=','0123456789') <> '' THEN
        IFoundIt := TRUE;
      IF MyPos = STRLEN(SourceString) THEN BEGIN
        IFoundIt := TRUE;
        MyPos := 0; // no non-numeric value found, so return 0
    UNTIL IFoundIt;
    MESSAGE('position is ' + format(MyPos));
    That should find the first non-numeric character in SourceString. So then you wrap it in a function and use return value.
  • SPost29SPost29 Member Posts: 148
    how about
    mystr := '10-98765';
    FOR i := 1 TO STRLEN(mystr) DO BEGIN
      IF NOT (mystr[i] IN [48..57]) THEN BEGIN  // ascii for 0 thru 9
        newstr := COPYSTR(mystr,i+1);
        i := STRLEN(mystr);  // drops out of for statement
  • DenSterDenSter Member Posts: 8,214
    so how do you get the ascii value out of the char? I tried with MESSAGE, but that returns the alphanumeric character.
  • SPost29SPost29 Member Posts: 148
    Chars can be treated as integers

    AsciiNo is integer
    mystr is text
    mystr := '10-2376'
    AsciiNo:= mystr[2];  // save char value as integer (ie the ascii value)
    message('ASCII No. is %1',AsciiNo);

    Message returns 48 which is ASCII No. for 0 (zero)
  • kinekine Member Posts: 12,562
      i := 1;
      while (mystr[i] in ['0'..'9']) and (i<= StrLen(mystr)) do
        i := i+1;
      if i>StrLen(mystr) then
        Exit(0)    //only numbers in string...
        Exit(i);    //return the position of the non-numeric character

    That's all folks... 8)
    Kamil Sacek
    MVP - Dynamics NAV
    My BLOG
    NAVERTICA a.s.
  • DenSterDenSter Member Posts: 8,214
    Yeah right, with code samples from two other people I can write really efficient code too :mrgreen:
  • mickbarrsmickbarrs Member Posts: 17
    I just added the = FALSE to the second line. This then tells me the line number where the first non-numeric character is.

    FOR i := 1 TO STRLEN(pTxtNumber) DO BEGIN
    Pos := i;

    IntNumber := 0;
    IF Pos <> 0 THEN BEGIN
    Alpha := DELSTR(pTxtNumber, 1, Pos);
    EVALUATE(IntNumber, Alpha);

    Thanks for the help!!!
  • DenSterDenSter Member Posts: 8,214
    If your goal is to generate an error if the code contains a non numeric character, why not just do EVALUATE(MyInt,TheWholeThing)?
  • mickbarrsmickbarrs Member Posts: 17
    The code below by Spost29 does just the trick. Mine works but this is a lot clearer.

    I just wanted to take the part of the string after the non-numeric character which in this case is '-'. So i wanted to return 98765.

    mystr := '10-98765';

    FOR i := 1 TO STRLEN(mystr) DO BEGIN
    IF NOT (mystr IN [48..57]) THEN BEGIN // ascii for 0 thru 9
    newstr := COPYSTR(mystr,i+1);
    i := STRLEN(mystr); // drops out of for statement


  • DenSterDenSter Member Posts: 8,214
    how about:
    mystr := '10-98765';
    FOR i := 1 TO STRLEN(mystr) DO BEGIN
      IF NOT (mystr[i] IN [48..57]) THEN 
        mystr := DELCHR(mystr,'=',format(mystr[i]));
  • mickbarrsmickbarrs Member Posts: 17
    Thanks for that. Will give it a try on Monday!!! :D
  • cdurmazcdurmaz Member Posts: 3
    after 12 years, the post really helped me about my phone number validation. thank you all, especially @DenSter
  • DenSterDenSter Member Posts: 8,214
    the gift that keeps giving :) I think it is so cool that these old posts are still helping people
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