java - Javaの文字列から長い/浮動小数点数を抽出する

Question

このような入力があります ==>
12.99 で 2 本
3.99 でポテトチップス 4 つ

各行から数値を抽出し、変数に格納します。

Answer 1

以下を使用できます。

Pattern p = Pattern.compile("(\\d+)\\D+(\\d+(?:.\\d+)?)");
Matcher mr = p.matcher("4 potato chips at 3.99");
if (mr.find()) {
    System.out.println( mr.group(1) + " :: " + mr.group(2) );
}

出力：

4::3.99

Answer 2

正規表現

(\d+)[^\d]+([+-]?[0-9]{1,3}(?:,?[0-9]{3})*(?:\.[0-9]{2})?)

Debuggex デモ

---

説明（例）

/^(\d+)[^\d]+([+-]?[0-9]{1,3}(?:,?[0-9]{3})*(?:\.[0-9]{2})?)$/gm
^ Start of line
1st Capturing group (\d+)
    \d 1 to infinite times [greedy] Digit [0-9]
Negated char class [^\d] 1 to infinite times [greedy] matches any character except:
    \d Digit [0-9]
2nd Capturing group ([+-]?[0-9]{1,3}(?:,?[0-9]{3})*(?:\.[0-9]{2})?)
    Char class [+-] 0 to 1 times [greedy] matches:
        +- One of the following characters +-
    Char class [0-9] 1 to 3 times [greedy] matches:
        0-9 A character range between Literal 0 and Literal 9
    (?:,?[0-9]{3}) Non-capturing Group 0 to infinite times [greedy]
        , 0 to 1 times [greedy] Literal ,
    Char class [0-9] 3 times [greedy] matches:
        0-9 A character range between Literal 0 and Literal 9
    (?:\.[0-9]{2}) Non-capturing Group 0 to 1 times [greedy]
        \. Literal .
    Char class [0-9] 2 times [greedy] matches:
        0-9 A character range between Literal 0 and Literal 9
$ End of line
g modifier: global. All matches (don't return on first match)
m modifier: multi-line. Causes ^ and $ to match the begin/end of each line (not only begin/end of string)

キャプチャ グループ 1:数量を含む

キャプチャ グループ 2:金額を含む

---

ジャワ

try {
    Pattern regex = Pattern.compile("(\\d+)[^\\d]+([+-]?[0-9]{1,3}(?:,?[0-9]{3})*(?:\\.[0-9]{2})?)", Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE);
    Matcher regexMatcher = regex.matcher(subjectString);
    while (regexMatcher.find()) {
        for (int i = 1; i <= regexMatcher.groupCount(); i++) {
            // matched text: regexMatcher.group(i)
            // match start: regexMatcher.start(i)
            // match end: regexMatcher.end(i)
        }
    } 
} catch (PatternSyntaxException ex) {
    // Syntax error in the regular expression
}

注:この Java は単なる例です。私は Java でコーディングしていません。