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* update presentations * CLICKHOUSE-2936: redirect from clickhouse.yandex.ru and clickhouse.yandex.com * update submodule * lost files * CLICKHOUSE-2981: prefer sphinx docs over original reference * CLICKHOUSE-2981: docs styles more similar to main website + add flags to switch language links * update presentations * Less confusing directory structure (docs -> doc/reference/) * Minify sphinx docs too * Website release script: fail fast + pass docker hash on deploy * Do not underline links in docs * shorter * cleanup docker images * tune nginx config * CLICKHOUSE-3043: get rid of habrastorage links * Lost translation * CLICKHOUSE-2936: temporary client-side redirect * behaves weird in test * put redirect back * CLICKHOUSE-3047: copy docs txts to public too * move to proper file * remove old pages to avoid confusion * Remove reference redirect warning for now * Refresh README.md * Yellow buttons in docs * Use svg flags instead of unicode ones in docs * fix test website instance * Put flags to separate files * wrong flag * Copy Yandex.Metrica introduction from main page to docs * Yet another home page structure change, couple new blocks (CLICKHOUSE-3045) * Update Contacts section * CLICKHOUSE-2849: more detailed legal information * CLICKHOUSE-2978 preparation - split by files * More changes in Contacts block * Tune texts on index page * update presentations * One more benchmark * Add usage sections to index page, adapted from slides * Get the roadmap started, based on slides from last ClickHouse Meetup * CLICKHOUSE-2977: some rendering tuning * Get rid of excessive section in the end of getting started * Make headers linkable * CLICKHOUSE-2981: links to editing reference - https://github.com/yandex/ClickHouse/issues/849 * CLICKHOUSE-2981: fix mobile styles in docs * Ban crawling of duplicating docs * Open some external links in new tab * Ban old docs too * Lots of trivial fixes in english docs * Lots of trivial fixes in russian docs * Remove getting started copies in markdown * Add Yandex.Webmaster * Fix some sphinx warnings * More warnings fixed in english docs * More sphinx warnings fixed * Add code-block:: text * More code-block:: text * These headers look not that well * Better switch between documentation languages * merge use_case.rst into ya_metrika_task.rst * Edit the agg_functions.rst texts * Add lost empty lines * Lost blank lines * Add new logo sizes * update presentations * Next step in migrating to new documentation * Fix all warnings in en reference * Fix all warnings in ru reference * Re-arrange existing reference * Move operation tips to main reference * Fix typos noticed by milovidov@ * Get rid of zookeeper.md * Looks like duplicate of tutorial.html * Fix some mess with html tags in tutorial * No idea why nobody noticed this before, but it was completely not clear whet to get the data * Match code block styling between main and tutorial pages (in favor of the latter) * Get rid of some copypaste in tutorial * Normalize header styles * Move example_datasets to sphinx * Move presentations submodule to website * Move and update README.md * No point in duplicating articles from habrahabr here * Move development-related docs as is for now * doc/reference/ -> docs/ (to match the URL on website) * Adapt links to match the previous commit * Adapt development docs to rst (still lacks translation and strikethrough support) * clean on release * blacklist presentations in gulp * strikethrough support in sphinx * just copy development folder for now * fix weird introduction in style article * Style guide translation (WIP) * Finish style guide translation to English * gulp clean separately * Update year in LICENSE * Initial CONTRIBUTING.md * Fix remaining links to old docs in tutorial * Some tutorial fixes * Typo * Another typo * Update list of authors from yandex-team accoding to git log
81 lines
3.6 KiB
ReStructuredText
81 lines
3.6 KiB
ReStructuredText
Functions for searching and replacing in strings
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------------------------------------------------
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replaceOne(haystack, pattern, replacement)
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Replaces the first occurrence, if it exists, of the 'pattern' substring in 'haystack' with the 'replacement' substring.
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Hereafter, 'pattern' and 'replacement' must be constants.
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replaceAll(haystack, pattern, replacement)
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Replaces all occurrences of the 'pattern' substring in 'haystack' with the 'replacement' substring.
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replaceRegexpOne(haystack, pattern, replacement)
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Replacement using the 'pattern' regular expression. A re2 regular expression. Replaces only the first occurrence, if it exists.
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A pattern can be specified as 'replacement'. This pattern can include substitutions \0-\9\.
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The substitution \0 includes the entire regular expression.
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The substitutions \1-\9 include the subpattern corresponding to the number.
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In order to specify the \ symbol in a pattern, you must use a \ symbol to escape it.
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Also keep in mind that a string literal requires an extra escape.
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Example 1. Converting the date to American format:
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.. code-block:: sql
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SELECT DISTINCT
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EventDate,
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replaceRegexpOne(toString(EventDate), '(\\d{4})-(\\d{2})-(\\d{2})', '\\2/\\3/\\1') AS res
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FROM test.hits
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LIMIT 7
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FORMAT TabSeparated
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.. code-block:: text
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2014-03-17 03/17/2014
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2014-03-18 03/18/2014
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2014-03-19 03/19/2014
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2014-03-20 03/20/2014
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2014-03-21 03/21/2014
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2014-03-22 03/22/2014
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2014-03-23 03/23/2014
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Example 2. Copy the string ten times:
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.. code-block:: sql
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SELECT replaceRegexpOne('Hello, World!', '.*', '\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0') AS res
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.. code-block:: text
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┌─res────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
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│ Hello, World!Hello, World!Hello, World!Hello, World!Hello, World!Hello, World!Hello, World!Hello, World!Hello, World!Hello, World! │
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└────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
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replaceRegexpAll(haystack, pattern, replacement)
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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This does the same thing, but replaces all the occurrences. Example:
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.. code-block:: sql
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SELECT replaceRegexpAll('Hello, World!', '.', '\\0\\0') AS res
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.. code-block:: text
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┌─res────────────────────────┐
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│ HHeelllloo,, WWoorrlldd!! │
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└────────────────────────────┘
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As an exception, if a regular expression worked on an empty substring, the replacement is not made more than once.
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Example:
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.. code-block:: sql
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SELECT replaceRegexpAll('Hello, World!', '^', 'here: ') AS res
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.. code-block:: text
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┌─res─────────────────┐
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│ here: Hello, World! │
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└─────────────────────┘
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