问题
So i have this code:
Pattern pattern = Pattern.compile("\\d*(\\s\\d+\\.)*\\s*[-\\+\\*/\\$£]");
String input = "4.0 5.0 2.0 / + 7.0 - 11.0 34.0 2.0 / 3.0 / 1.0 * +";
Matcher matcher = pattern.matcher(input);
List<String> output = new ArrayList<>();
while (matcher.find()) {
output.add(matcher.group());
}
When i was working on just parsing integers the regex was of course fine however i now need it to take into account that there can be a . to represent a floating point.
Wondering if someone can help me with adding this in
expected output should be :
4.0 5.0 2.0 /
+
7.0 -
11.0 34.0 2.0 /
3.0 /
1.0 *
+
回答1:
This would produce the output you want. The part next to the Logical OR | operator will matches the [-+*/$£] symbols from the remaining sub-string.
Pattern pattern = Pattern.compile("\\d+(?:\\.\\d+)?(\\s\\d+(?:\\.\\d+)?)*\\s*[-+*/$£]|[-+*/$£]");
String input = "4.0 5.0 2.0 / + 7.0 - 11.0 34.0 2.0 / 3.0 / 1.0 * +";
Matcher matcher = pattern.matcher(input);
ArrayList<String> output = new ArrayList<String>();
while (matcher.find()) {
output.add(matcher.group());
}
for (String s: output)
{
System.out.println(s);
}
Output:
4.0 5.0 2.0 /
+
7.0 -
11.0 34.0 2.0 /
3.0 /
1.0 *
+
来源：https://stackoverflow.com/questions/27602066/need-to-change-regex-for-additional-postfix-criteria