How to check a string contains only digits and one occurrence of a decimal point?

Question

My idea is something like this but I dont know the correct code

if (mystring.matches(\"[0-9.]+\")){
  //do something here
}else{
  //do something here
}
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Answer 1

Use the below RegEx its solve your proble

1. allow 2 decimal places ( e.g 0.00 to 9.99)

   ^[0-9]{1}[.]{1}[0-9]{2}$
   
   This RegEx states:
   
   1. ^ means the string must start with this.
   2. [0-9] accept 0 to 9 digit.
   3. {1} number length is one.
   4. [.] accept next character dot.
   5. [0-9] accept 0 to 9 digit.
   6. {2} number length is one.
   

2. allow 1 decimal places ( e.g 0.0 to 9.9)

   ^[0-9]{1}[.]{1}[0-9]{1}$
   
   This RegEx states:
   
   1. ^ means the string must start with this.
   2. [0-9] accept 0 to 9 digit.
   3. {1} number length is one.
   4. [.] accept next character dot.
   5. [0-9] accept 0 to 9 digit.
   6. {1} number length is one.