How to check if string contains a certain substring like [3:0]

Question

I am working on a project where i need to search for a particular string token and find if this token has the [3:0] format of number, how can i check it? i searched for reference on stack overflow, i could find how to search "{my string }:" in a string like the following:

String myStr = "this is {my string: } ok";
if (myStr.trim().contains("{my string: }")) {
    //Do something.
} 

But, could not find how to search if a string contains a number in the regular expression, i tried using the following, but it did not work:

String myStr = "this is [3 string: ] ok";
if (myStr.trim().contains("[\\d string: ]")) {
    //Do something.
} 

Please help!

Answer 1

for "[int:int]" use \\[\\d*:\\d*\\]  it's working

Answer 2

You cannot use a regex inside String#contains , instead, use .matches() with a regex.

To match [3 string: ] -like patterns inside larger strings (where string is a literal word string ), use a regex like (?s).*\\\\[\\\\d+\\\\s+string:\\\\s*\\\\].* :

String myStr = "this is [3 string: ] ok";
if (myStr.matches("(?s).*\\[\\d+\\s+string:\\s*\\].*")) {
    System.out.println("FOUND");
} 

See IDEONE demo

The regex will match any number of any characters from the start of string with .* (as many as possible) before a [ +1 or more digits+1 or more whitespace+ string: +0 or more whitespace+ ] +0 or more any characters up to the end of string.

The (?s) internal modifier makes the dot match newline characters, too.

Note we need .* on both sides because .matches() requires a full string match.

To match [3:3] -like pattern inside larger strings use:

"(?s).*\\[\\d+\\s*:\\s*\\d+\\].*"

See another IDEONE demo

Remove \\\\s* if whitespace around : is not allowed.