CODEWITHSUNDEEP
stringlistdart
user2843482
user2843482

Reputation: 1

Validate if a text has only letters and spaces

I'm new to programming and I'm using Dart for a “introduction to programming“ course.

I'd like to write a code to validate if a text has only letter and space. I've found this for validate spaces. 

function validate() {
  var field = document.getElementById("myField");
  if (field.value.replace(/ /g, "").length == 0)  {
    alert("Please enter some data (not spaces!)");
  }
}

Thanks in advance, also I would need to write a string variable with sentences of different lengths and a function that finds the longest sentence. Any pointers?

Upvotes: 0

Views: 1275

Answers (1)

Nathanial
Nathanial

Reputation: 2257

[^a-z ] matches anything that is not a lowercase letter or space. caseSensitive: false makes it not match upper case either. 

RegExp exp = new RegExp(r"[^a-z ]", caseSensitive: false);

print(exp.allMatches("this is valid").length == 0);
print(exp.allMatches("ThIs Is VaLiD").length == 0);
print(exp.allMatches("Th1s 1s NOT val1d").length == 0);

You can use exp.allMatches("string").length to find the number of characters that are not alpha or whitespace. so you can use:

if (exp.allMatches(field.value).length > 0)  {
    alert("Please enter some data (not spaces!)");
}

Upvotes: 2

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