How to validate string

Question

Hi,

    i have string value with alphanumeric [ XYZ001]

   it is not accept the special character so how i add validation

var string input= "XYZ001";

Input.find( aChar, aStartIndex );  //this implemention is correct

how we filter the special character from input string.please help me to resolve this.

 

With Regards,

Ramesh.g

Answer 1

Hello Ramesh.g,

I assume the string has been entered by the user and you want to verify whether the string content is correct. In such case you would implement a loop to iterate through the string characters and test character by character whether it corresponds to the expected syntax. For example, if the string is allowed to store ascii characters A-Z and digits 0-9, following could be the implementation:

var string text  = .... // your string
var int32  len   = text.length;
var bool   valid = len > 0;
var int32  inx;

for ( inx = 0; ( inx < len ) && valid; inx = inx + 1 )
  if ((( text[inx] < 'A' ) || ( text[inx] > 'Z' )) &&
      (( text[inx] < '0' ) || ( text[inx] > '9' )))
    valid = false;

if ( !valid )
  trace "The text is not valid";

I hope it helps you further.

Best regards

Paul Banach

Comments

Hi Paul,

Thanks for the quick update .It is working fine.

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Hi Paul,

How the above code can be modified to validate a string which need to be contain minimum of one lower case, one upper case, one digit key and one special character. Please support.

Regards,

Sazna

---

Hello Sazna,

following could be an example demonstrating such evaluation. The string specialChars has to be adapted to your needs, depending on what you mean with special chars:

var string specialChars   = "+*#,;.:-_!§%%$$/()[]";
var string text           = "Some Text 7 +";
var int32  len            = text.length;
var bool   hasLowerCase   = false;
var bool   hasUpperCase   = false;
var bool   hasDigitSign   = false;
var bool   hasSpecialChar = false;
var int32  inx;

for ( inx = 0; ( inx < len ); inx = inx + 1 )
{
  var char c = text[inx];

  hasLowerCase   |= ( c >= 'a' ) && ( c <= 'z' );
  hasUpperCase   |= ( c >= 'A' ) && ( c <= 'Z' );
  hasDigitSign   |= ( c >= '0' ) && ( c <= '9' );
  hasSpecialChar |= specialChars.find( c, 0 ) >= 0;
}

var bool valid = hasLowerCase && hasUpperCase && hasDigitSign && hasSpecialChar;

Best regards

Paul Banach

---

Hi Paul,

var string specialChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
var string tempPassword;
var bool   hasLowerCase   = false;
var bool   hasUpperCase   = false;
var bool   hasDigitSign   = false;
var bool valid = true;
var int32  inx;

do{
// Desired number of signs in the resulting string
var int32  count = 6;
tempPassword = "";
 
// Compose the string of random characters
while ( count-- > 0 )
{ 
  tempPassword += specialChars[ math_rand( 0, specialChars.length - 1 )];
}
 
//Validity check
for ( inx = 0; ( inx < tempPassword.length ); inx = inx + 1 )
      {
        var char c = tempPassword[inx];
     
        hasLowerCase   |= ( c >= 'a' ) && ( c <= 'z' );
        hasUpperCase   |= ( c >= 'A' ) && ( c <= 'Z' );
        hasDigitSign   |= ( c >= '0' ) && ( c <= '9' );
        //hasSpecialChar |= specialChars.find( c, 0 ) >= 0;
    
      }
 
valid = hasLowerCase && hasUpperCase && hasDigitSign ; 
 
}
while(valid == false);

// 'tempPassword' contains the random string
trace tempPassword;

 Here I am using validation check using the above method, But randomly it allows a string to exit from the loop without minimum of one lowercase or upper case or digit key.

For example If I generate a string "xRTdTu", it should be not validated but sometimes it is validating these type of strings as correct one. Why this behavior occurs randomly? 

Regards,

Sazna.

---

Hello Sazna,

the variables hasLowerCase, hasUpperCase and hasDigitSign are nor reset when repeating the operation in the do..while loop. Move the definition of the variables inside the do..while loop.

Best regards

Paul Banach

---

Hi Paul,

Thank you for the explanation.

Regards,

Sazna.