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Deprecated: Return type of WP_Theme::offsetUnset($offset) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /usr/home/bugyo/public_html/b-log/wp-includes/class-wp-theme.php on line 544

Deprecated: Using ${var} in strings is deprecated, use {$var} instead in /usr/home/bugyo/public_html/b-log/wp-includes/comment-template.php on line 1739

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Deprecated: Return type of WP_REST_Request::offsetUnset($offset) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /usr/home/bugyo/public_html/b-log/wp-includes/rest-api/class-wp-rest-request.php on line 1003

Deprecated: Return type of WP_Block_List::current() should either be compatible with Iterator::current(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /usr/home/bugyo/public_html/b-log/wp-includes/class-wp-block-list.php on line 151

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Deprecated: Return type of WP_Block_List::key() should either be compatible with Iterator::key(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /usr/home/bugyo/public_html/b-log/wp-includes/class-wp-block-list.php on line 164

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Deprecated: Return type of WP_Block_List::rewind() should either be compatible with Iterator::rewind(): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /usr/home/bugyo/public_html/b-log/wp-includes/class-wp-block-list.php on line 138

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Deprecated: Return type of WP_Block_List::offsetSet($index, $value) should either be compatible with ArrayAccess::offsetSet(mixed $offset, mixed $value): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /usr/home/bugyo/public_html/b-log/wp-includes/class-wp-block-list.php on line 110

Deprecated: Return type of WP_Block_List::offsetUnset($index) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /usr/home/bugyo/public_html/b-log/wp-includes/class-wp-block-list.php on line 127

Deprecated: Return type of WP_Block_List::count() should either be compatible with Countable::count(): int, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /usr/home/bugyo/public_html/b-log/wp-includes/class-wp-block-list.php on line 199

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Deprecated: Return type of Requests_Cookie_Jar::offsetUnset($key) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /usr/home/bugyo/public_html/b-log/wp-includes/Requests/Cookie/Jar.php on line 102

Deprecated: Return type of Requests_Cookie_Jar::getIterator() should either be compatible with IteratorAggregate::getIterator(): Traversable, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /usr/home/bugyo/public_html/b-log/wp-includes/Requests/Cookie/Jar.php on line 111

Deprecated: Return type of Requests_Utility_CaseInsensitiveDictionary::offsetExists($key) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /usr/home/bugyo/public_html/b-log/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 40

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Deprecated: Creation of dynamic property WP_Term::$object_id is deprecated in /usr/home/bugyo/public_html/b-log/wp-includes/class-wp-term.php on line 198

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Deprecated: Creation of dynamic property WP_Term::$object_id is deprecated in /usr/home/bugyo/public_html/b-log/wp-includes/class-wp-term.php on line 198

Deprecated: Creation of dynamic property WP_Term::$object_id is deprecated in /usr/home/bugyo/public_html/b-log/wp-includes/class-wp-term.php on line 198
[Clojure] 空リストか否か – B-LOG

[Clojure] 空リストか否か

Posted on 2013 年 2 月 11 日 by bugyo — No Comments ↓

Clojure では nil と空リストは同じではない。

  (= nil '()) => false

よって、再帰の停止条件などでは空リストか否かを返す述語 empty? を使う。

  (defn sum [lst]
    (if (empty? lst)
      0
      (+ (first lst) (sum (rest lst)))))

Deprecated: Creation of dynamic property WP_Query::$comments_by_type is deprecated in /usr/home/bugyo/public_html/b-log/wp-includes/comment-template.php on line 1528

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