CODEWITHSUNDEEP
javaregexarithmetic-expressions
MedAl
MedAl

Reputation: 475

Regular expression for arithmetic expression

I,m trying to write a regex to check if the given string is like a + b, 2 + a + b, 3 + 6 * 9 + 6 * 5 + a * b, etc...

Only + and * operators.

I tried

if (str.matches("(\\d|\\w \\+|\\*){1,} \\d|\\w"))

Unfortunately it only handles cases like 3 * 7 ... (numeric * numeric).

Waiting for your answers, thanks for reading me.

Upvotes: 5

Views: 8274

Answers (2)

Steve Chaloner
Steve Chaloner

Reputation: 8202

This will handle cases of simple and chained calculations

[0-9A-Za-a]*( ){0,}([+-/*]( ){0,}[0-9A-Za-a]*( ){0,})*

This would match, for example

  • 1+2
  • 1 + 2
  • 1 + a * 14 / 9

(You can change the operators you want by updating [+-/*])

Upvotes: 2

Avinash Raj
Avinash Raj

Reputation: 174706

Put * and + inside a character class.

str.matches("\\w(?:\\s[+*]\\s\\w)+");

DEMO

Upvotes: 5

Related Questions