本文整理了Java中fj.data.List.groupBy()方法的一些代码示例，展示了List.groupBy()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。List.groupBy()方法的具体详情如下：
包路径：fj.data.List
类名称：List
方法名：groupBy

List.groupBy介绍

[英]Groups the elements of this list by a given keyFunction into a TreeMap. The ordering of the keys is determined by fj.Ord#hashOrd() (ie. Object#hasCode). This is not safe and therefore this method is deprecated.
[中]按给定的键函数将此列表的元素分组到树映射中。键的顺序由fj决定。Ord#hashOrd（）（即Object#hasCode）。这是不安全的，因此不推荐使用此方法。

代码示例

代码示例来源：origin: org.functionaljava/functionaljava

/**
 * Groups the elements of this list by a given keyFunction into a {@link TreeMap}.
 *
 * @param keyFunction The function to select the keys for the map.
 * @param keyOrd An order for the keys of the tree map.
 * @return A TreeMap containing the keys with the accumulated list of matched elements.
 */
public final <B> TreeMap<B, List<A>> groupBy(final F<A, B> keyFunction, final Ord<B> keyOrd) {
 return groupBy(keyFunction, identity(), keyOrd);
}

代码示例来源：origin: org.functionaljava/functionaljava

/**
 * Groups the elements of this list by a given keyFunction into a {@link TreeMap}.
 * The ordering of the keys is determined by {@link fj.Ord#hashOrd()} (ie. Object#hasCode).
 * This is not safe and therefore this method is deprecated.
 *
 * @param keyFunction The function to select the keys for the map.
 * @return A TreeMap containing the keys with the accumulated list of matched elements.
 *
 * @deprecated As of release 4.7, use {@link #groupBy(F, Ord)}
 */
@Deprecated
public final <B> TreeMap<B, List<A>> groupBy(final F<A, B> keyFunction) {
 return groupBy(keyFunction, Ord.hashOrd());
}

代码示例来源：origin: org.functionaljava/functionaljava

/**
 * Groups the elements of this list by a given keyFunction into a {@link TreeMap} and transforms
 * the matching elements with the given valueFunction. The ordering of the keys is determined by
 * the keyOrd parameter.
 *
 * @param keyFunction The function to select the keys for the map.
 * @param valueFunction The function to apply on each matching value.
 * @param keyOrd An order for the keys of the tree map.
 * @return A TreeMap containing the keys with the accumulated list of matched and mapped elements.
 */
public final <B, C> TreeMap<B, List<C>> groupBy(
  final F<A, B> keyFunction,
  final F<A, C> valueFunction,
  final Ord<B> keyOrd) {
 return this.groupBy(keyFunction, valueFunction, List.nil(), List::cons, keyOrd);
}

代码示例来源：origin: org.functionaljava/functionaljava

/**
 * Groups the elements of this list by a given keyFunction into a {@link TreeMap} and transforms
 * the matching elements with the given valueFunction. The ordering of the keys is determined by
 * {@link fj.Ord#hashOrd()} (ie. Object#hasCode).
 * This is not safe and therefore this method is deprecated.
 *
 * @param keyFunction The function to select the keys for the map.
 * @param valueFunction The function to apply on each matching value.
 * @return A TreeMap containing the keys with the accumulated list of matched and mapped elements.
 *
 * @deprecated As of release 4.7, use {@link #groupBy(F, F, Ord)}
 */
@Deprecated
public final <B, C> TreeMap<B, List<C>> groupBy(
  final F<A, B> keyFunction,
  final F<A, C> valueFunction) {
 return this.groupBy(keyFunction, valueFunction, Ord.hashOrd());
}

代码示例来源：origin: org.functionaljava/functionaljava

/**
 * Groups the elements of this list by a given keyFunction into a {@link TreeMap} and transforms
 * the matching elements with the given valueFunction. The ordering of the keys is determined by
 * the keyOrd parameter.
 *
 * @param keyFunction The function to select the keys for the map.
 * @param valueFunction The function to apply on each matching value.
 * @param monoid A monoid, which defines the accumulator for the values and the zero value.
 * @param keyOrd An order for the keys of the tree map.
 * @return A TreeMap containing the keys with the accumulated list of matched and mapped elements.
 */
public final <B, C> TreeMap<B, C> groupBy(
  final F<A, B> keyFunction,
  final F<A, C> valueFunction,
  final Monoid<C> monoid,
  final Ord<B> keyOrd) {
 return groupBy(keyFunction, valueFunction, monoid.zero(),
   uncurryF2(monoid.sum()), keyOrd);
}

代码示例来源：origin: it.unibz.inf.ontop/ontop-optimization

TreeMap<Variable, Set<Variable>> commonMap = renamingPairs.groupBy(P2.<Variable, Variable>__1(),
    P2.<Variable, Variable>__2()).