src/org/nutz/lang/util/NutMap.java
@Override
    public NutMap pickBy(String regex) {
        if (Strings.isBlank(regex))
            return this.duplicate();
        boolean isNot = regex.startsWith("!");
        Pattern p = Regex.getPattern(isNot ? regex.substring(1) : regex);
        return pickBy(p, isNot);
    }
@Override
    public NutMap pickBy(String regex) {
        if (Strings.isBlank(regex))
            return this.duplicate();
        boolean isNot = regex.startsWith("!");
        Pattern p = Regex.getPattern(isNot ? regex.substring(1) : regex);
        return pickBy(p, isNot);
    }
从 Map 里挑选一些键生成一个新的 Map

@param regex
匹配键的正则表达式，"!" 开头，表示取反
@return 新 Map