Question

I have a String that has data such as:

String data = "Some information and then value1=17561.2 and then value2=15672.2"

How do I return 17561.2 most efficiently in Java?

String queryString = "value1";

while data.charAt(outputStr.indexOf(queryString)+queryString.length()) is a number

    -save it to an array
    which you later convert to a String

elihw

This seems kind-of convoluted.

Would regexs be perfect here? How would I craft a regular expression to do this?

Answer 1

To find a decimal number (or an int) in a string, you could use the regular expression

[+-]?(?:\d*\.\d+|\d+)

This will not find floats in exponential notation, though (1.2E15 or some such).

Explanation:

[+-]?     # optional sign
(?:       # either
 \d*\.\d+ # float with optional integer part
 |        # or
 \d+      # just integer
)

In Java (to iterate over all matches in a string):

Pattern regex = Pattern.compile("[+-]?(?:\\d*\\.\\d+|\\d+)");
Matcher regexMatcher = regex.matcher(subjectString);
while (regexMatcher.find()) {
    // matched text: regexMatcher.group()
    // match start: regexMatcher.start()
    // match end: regexMatcher.end()
}