Regex for a name and number dart

Question

I need to validate a form that a user provides their name and a number. I have a regex that is supposed to make sure the name contains only letters and nothing else and also for the number input i need to make sure only numbers are in the field. The code I have looks like

 validator: (value) => value.isEmpty
                        ? 'Enter Your Name'
                        : RegExp(
                                '!@#<>?":_``~;[]\|=-+)(*&^%1234567890')
                            ? 'Enter a Valid Name'
                            : null,

can i get a regex expression that validates a name in such a way if any special character or number is inputted it becomes wrong meaning only letters are valid and another that validates a number in such a way if an alphabetical letter or any special character is inputted it becomes wrong meaning only the input of a number is valid

Looks like you wanted `RegExp(r'[!@#<>?":_\`~;[\]\\|=+)(*&^%0-9-]').hasMatch(value)`. You need to use a raw string literal, put `-` at the end and escape `]` and ``\`` chars, then check if there is a match with `.hasMatch(value)`. `[0123456789]` = `[0-9]`. — Wiktor Stribiżew, Aug 24 '18 at 21:12
This works for the Name RegExp. Can you explain for the number one. In this one, the user is presented with the number keyboard so some characters are not important as such. I have just copied the name Regex and pasted it here but removed `0-9` in order to be able to input the numbers. Problem is, when a space is inserted, it still counts it as a value. How can i correct this. — Taio, Aug 25 '18 at 08:14

score 20 · Answer 1 · answered Aug 24 '18 at 14:08

20

Create a static final field for the RegExp to avoid creating a new instance every time a value is checked. Creating a RegExp is expensive.

static final RegExp nameRegExp = RegExp('[a-zA-Z]'); 
    // or RegExp(r'\p{L}'); // see https://stackoverflow.com/questions/3617797/regex-to-match-only-letters 
static final RegExp numberRegExp = RegExp(r'\d');

Then use it like

validator: (value) => value.isEmpty 
    ? 'Enter Your Name'
    : (nameRegExp.hasMatch(value) 
        ? null 
        : 'Enter a Valid Name');

answered Aug 24 '18 at 14:08

Günter Zöchbauer

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Both are not working. In the question I specified I need something that will not accept anything else other than alphabetical letters, for the name. And for the number input, numbers only not a special character or anything else. This regex thing is awfully stressful – Taio Aug 24 '18 at 17:32
eg. for the name if it is **gunter zochbauer** if a comma is present somewhere it becomes wrong – Taio Aug 24 '18 at 17:35
You demanded "only letters". Did you check the commented out alternative. If this us not what you want please formulate your question more precise. – Günter Zöchbauer Aug 24 '18 at 17:50
i have edited the original question to further explain it. Apologies – Taio Aug 24 '18 at 18:08
I still don't think it is unclear how my answer does not answer your question. `RegExp('[a-zA-Z\ ]')` validates to `true` for my name. – Günter Zöchbauer Aug 24 '18 at 20:12

score 13 · Accepted Answer · answered Aug 25 '18 at 20:38

It seems to me you want

RegExp(r'[!@#<>?":_`~;[\]\\|=+)(*&^%0-9-]').hasMatch(value)

Note that you need to use a raw string literal, put - at the end and escape ] and \ chars inside the resulting character class, then check if there is a match with .hasMatch(value). Notre also that [0123456789] is equal to [0-9].

As for the second pattern, you can remove the digit range from the regex (as you need to allow it) and add a \s pattern (\s matches any whitespace char) to disallow whitespace in the input:

RegExp(r'[!@#<>?":_`~;[\]\\|=+)(*&^%\s-]').hasMatch(value)

score 0 · Answer 3 · answered Mar 19 '21 at 13:25

Base on this answer and this information:

\p{L} or \p{Letter}: any kind of letter from any language.

Reference: http://www.regular-expressions.info/unicode.html

The regex for a name validation:

RegExp(r"^[\p{L} ,.'-]*$",
      caseSensitive: false, unicode: true, dotAll: true)
  .hasMatch(my_name)

Regex for a name and number dart

3 Answers3