* number of nodes as follows:
   *
   * {@snippet :
   * Iterables.limit(Traverser.forGraph(graph).breadthFirst(node), maxNumberOfNodes);
   * }
   *
   * <p>See <a href="https://en.wikipedia.org/wiki/Breadth-first_search">Wikipedia</a> for more
   * info.
   *
   * @throws IllegalArgumentException if {@code startNode} is not an element of the graph
   */
  public final Iterable<N> breadthFirst(N startNode) {

   * by RFC 3720, Section 12.1.
   *
   * <p>This function is best understood as a <a
   * href="https://en.wikipedia.org/wiki/Checksum">checksum</a> rather than a true <a
   * href="https://en.wikipedia.org/wiki/Hash_function">hash function</a>.
   *
   * @since 18.0
   */
  public static HashFunction crc32c() {
    return Crc32cHashFunction.CRC_32_C;
  }

## Conclusion { #conclusion }

With this you should have a basic understanding of what **environment variables** are and how to use them in Python.

You can also read more about them in the [Wikipedia for Environment Variable](https://en.wikipedia.org/wiki/Environment_variable).

</div>

////

この情報は、[Virtual Environments](virtual-environments.md)について学ぶ際にも役立ちます。

## まとめ { #conclusion }

これで、**環境変数**とは何か、Pythonでどのように使用するかについて、基本的な理解が得られたはずです。

環境変数についての詳細は、[Wikipedia の環境変数](https://en.wikipedia.org/wiki/Environment_variable)も参照してください。

多くの場合、環境変数がどのように役立ち、すぐに適用できるのかはあまり明確ではありません。しかし、開発中のさまざまなシナリオで何度も登場するため、知っておくとよいでしょう。

  /* image types */
  /**
   * <a href="https://en.wikipedia.org/wiki/BMP_file_format">Bitmap file format</a> ({@code bmp}
   * files).
   *
   * @since 13.0
   */
  public static final MediaType BMP = createConstant(IMAGE_TYPE, "bmp");

  /**
   * The <a href="https://en.wikipedia.org/wiki/Camera_Image_File_Format">Canon Image File

 * definition in <a
 * href="http://stat.ethz.ch/R-manual/R-devel/library/stats/html/quantile.html">R</a>, and it is
 * described by <a
 * href="http://en.wikipedia.org/wiki/Quantile#Estimating_the_quantiles_of_a_population">
 * wikipedia</a> as providing "Linear interpolation of the modes for the order statistics for the
 * uniform distribution on [0,1]."
 *
 * <h3>Handling of non-finite values</h3>
 *

        Collector.Characteristics.UNORDERED);
  }

  /** Returns the number of values. */
  public long count() {
    return count;
  }

  /**
   * Returns the <a href="http://en.wikipedia.org/wiki/Arithmetic_mean">arithmetic mean</a> of the
   * values. The count must be non-zero.
   *
   * <p>If these values are a sample drawn from a population, this is also an unbiased estimator of

   *     power set size to exceed the {@code int} range)
   * @throws NullPointerException if {@code set} is or contains {@code null}
   * @see <a href="http://en.wikipedia.org/wiki/Power_set">Power set article at Wikipedia</a>
   * @since 4.0
   */
  public static <E> Set<Set<E>> powerSet(Set<E> set) {
    return new PowerSet<E>(set);
  }

    .bootstrapDnsHosts(InetAddress.getByName("8.8.4.4"), InetAddress.getByName("8.8.8.8"))
    .build()

  val client = bootstrapClient.newBuilder().dns(dns).build()
```

   *     power set size to exceed the {@code int} range)
   * @throws NullPointerException if {@code set} is or contains {@code null}
   * @see <a href="http://en.wikipedia.org/wiki/Power_set">Power set article at Wikipedia</a>
   * @since 4.0
   */
  public static <E> Set<Set<E>> powerSet(Set<E> set) {
    return new PowerSet<E>(set);
  }