Java substring keep only digits and decimal

Question

I have strings that I need to remove the trailing characters from. There are several types, here are some examples:

"82.882ft" "101in" "15.993ft³" "10.221mm"

Etc. I need to remove the length delimiters so I will be left with strings:

"82.882" "101" "15.993" "10.221"

Ideas?

I don't see a clean way to do this with substring functions. — ergonaut, Oct 19 '15 at 15:40
1. Find the index of the first character that isn't part of the number (only you can know precisely what characters are permissible within the numbers) 2. take the substring up to that point — DJClayworth, Oct 19 '15 at 15:44
Since the title of the other answer only said "non numeric characters", it didn't specify that it included a period (which is non numeric), thus I didn't think it was the same. Looking closer, they did include the period. — GregMa, Oct 19 '15 at 16:31

score 3 · Answer 1 · answered Oct 19 '15 at 15:44

3

Just use regex:

String result = input.replaceAll("[^0-9.]", "");

answered Oct 19 '15 at 15:44

Alex Salauyou

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score 3 · Accepted Answer · answered Oct 19 '15 at 15:46

3

Try using a replaceAll on the string, specifying all characters that are not a decimal point or number:

myString = myString.replaceAll("[^0-9\\.]","");

"^0-9\." means all characters that are not a number 0 through 9, or a decimal. The reason why we put two slashes are to escape the period, as it has a different connotation in a Java regex than the literal character '.'.

answered Oct 19 '15 at 15:46

MrPublic

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escaping `.` inside character class is actually not necessary – Alex Salauyou Oct 19 '15 at 15:49

score 0 · Answer 3 · answered Oct 19 '15 at 15:52

Regular Expressions probably works best for this.

    Pattern lp = Pattern.compile("([\\d.]+)(.*)");

    // Optional cleanup using Apache Commons StringUtils
    currentInput = StringUtils.upperCase(
            StringUtils.deleteWhitespace(currentInput));

    Matcher lpm = lp.matcher(currentInput);
    if( lpm.matches() )
    {
        // Values
        String value = lpm.group(1);

        // And the trailing chars for further processing
        String measure = lpm.group(2);
    }

Java substring keep only digits and decimal

3 Answers3