Regular expression: Difference between revisions

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{{LanguageSwitcher | content = [[Regular expression | English]], [[Regular expression in Mandarin|漢字]]}}
{{LanguageSwitcher | content = [[Regular expression | English]], [[Regular expression in Mandarin|漢字]]}}


<blockquote>'''Need Help?''' You can use the provided explanatory [[#regular-expression-online-tools|online tools]] to try debugging yourself.
{{Raise hand | text = '''Need Help?''' You can use the provided explanatory [[#regular-expression-online-tools|online tools]] to try debugging yourself. }}
</blockquote>
 


== Quick Reference Table ==
== Quick Reference Table ==
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Convert to:
Convert to:
<span id="method-1-sublime-text-emeditor"></span>
 
==== Method 1: Sublime Text, EmEditor ====
==== Method 1: Sublime Text, EmEditor ====


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# Click “Replace All”
# Click “Replace All”


<span id="method-3-microsoft-word"></span>
 
==== Method 3: Microsoft Word ====
==== Method 3: Microsoft Word ====


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# Click “Replace All”
# Click “Replace All”


<span id="method-4-sed-command-for-linux"></span>
==== Method 4: Sed command for Linux ====
==== Method 4: Sed command for Linux ====


<syntaxhighlight lang="bash">sed ':a;N;$!ba;s/\n/; /g' old.filename > new.filename</syntaxhighlight>
<syntaxhighlight lang="bash">sed ':a;N;$!ba;s/\n/; /g' old.filename > new.filename</syntaxhighlight>
<span id="find-ip-addresses-ipv4"></span>
 
=== Find IP Addresses (IPv4) ===
=== Find IP Addresses (IPv4) ===


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For Sublime Text v. 3.2.21: - Find: <code>(?:\d{1,3}\.){3}\d{1,3}</code>
For Sublime Text v. 3.2.21: - Find: <code>(?:\d{1,3}\.){3}\d{1,3}</code>


<span id="remove-black-squares-unix-line-endings-lf"></span>
=== Remove Black Squares (UNIX Line Endings LF) ===
=== Remove Black Squares (UNIX Line Endings LF) ===


Using Notepad++: 1. Menu: Find -&gt; Replace 2. Search mode: Check “Extended mode” - Find: <code>\n\n</code> (2 LF characters) - Replace with: <code>\r\n</code> (CR and LF)
Using Notepad++: 1. Menu: Find -&gt; Replace 2. Search mode: Check “Extended mode” - Find: <code>\n\n</code> (2 LF characters) - Replace with: <code>\r\n</code> (CR and LF)


<span id="add-quotes-around-elements"></span>
=== Add Quotes Around Elements ===
=== Add Quotes Around Elements ===


<span id="add-quotes-around-array-elements"></span>
==== Add Quotes Around Array Elements ====
==== Add Quotes Around Array Elements ====


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'''Method 3: Notepad++''' (Enable “Regular expression” search mode) - Find: <code>([^\s|,]+)</code> - Replace with: <code>'$1'</code> (for single quotes) or <code>&quot;$1&quot;</code> (for double quotes)
'''Method 3: Notepad++''' (Enable “Regular expression” search mode) - Find: <code>([^\s|,]+)</code> - Replace with: <code>'$1'</code> (for single quotes) or <code>&quot;$1&quot;</code> (for double quotes)


<span id="find-non-ascii-characters-chinesenon-english-text"></span>
=== Find Non-ASCII Characters (Chinese/Non-English Text) ===
=== Find Non-ASCII Characters (Chinese/Non-English Text) ===


<span id="in-google-sheets"></span>
==== In Google Sheets ====


<pre>[^\x00-\x80]+</pre>
<span id="in-libreoffice"></span>
==== In LibreOffice ====
==== In LibreOffice ====


<pre>[^\u0000-\u0080]+</pre>
<pre>[^\u0000-\u0080]+</pre>
<span id="find-chinese-characters-in-google-sheets"></span>
 
 
==== Find Chinese Characters in Google Sheets ====
==== Find Chinese Characters in Google Sheets ====


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<pre>=IF(REGEXMATCH(A2, &quot;[\一-\龥]&quot;), &quot;Chinese&quot;, &quot;English&quot;)</pre>
<pre>=IF(REGEXMATCH(A2, &quot;[\一-\龥]&quot;), &quot;Chinese&quot;, &quot;English&quot;)</pre>
<span id="find-chinese-characters-in-mysql"></span>


==== Find Non-ASCII Characters in Google Sheets ====
==== Find Non-ASCII Characters in Google Sheets ====
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FROM `table_name`
FROM `table_name`
WHERE `column_name` <> CONVERT(`column_name` USING ASCII)</syntaxhighlight>
WHERE `column_name` <> CONVERT(`column_name` USING ASCII)</syntaxhighlight>
<span id="find-chinese-characters-in-php"></span>
 
==== Find Chinese Characters in PHP ====
==== Find Chinese Characters in PHP ====


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preg_match_all($pattern, $string, $matches, PREG_OFFSET_CAPTURE);
preg_match_all($pattern, $string, $matches, PREG_OFFSET_CAPTURE);
var_dump($matches);</syntaxhighlight>
var_dump($matches);</syntaxhighlight>
<span id="find-ascii-characters-in-php"></span>
 
=== Find ASCII Characters in PHP ===
=== Find ASCII Characters in PHP ===


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     echo "Contains non-ASCII characters";
     echo "Contains non-ASCII characters";
}</syntaxhighlight>
}</syntaxhighlight>
<span id="remove-empty-lines"></span>
 
=== Remove Empty Lines ===
=== Remove Empty Lines ===


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'''Using Notepad++ v7.8.7:''' - Menu: Edit -&gt; Line Operations -&gt; Remove Empty Lines (Including Blank Lines)
'''Using Notepad++ v7.8.7:''' - Menu: Edit -&gt; Line Operations -&gt; Remove Empty Lines (Including Blank Lines)


<span id="find-non-whitespace-text"></span>
=== Find Non-Whitespace Text ===
=== Find Non-Whitespace Text ===


* Find: <code>[^\s]+</code>
* Find: <code>[^\s]+</code>


<span id="convert-symbol-separated-text-to-line-by-line-display"></span>
=== Convert Symbol-Separated Text to Line-by-Line Display ===
=== Convert Symbol-Separated Text to Line-by-Line Display ===


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'''Using Sublime Text or EmEditor:''' - Find: <code>([^、]+)([、]{1})</code> - Replace with: <code>\1\n</code>
'''Using Sublime Text or EmEditor:''' - Find: <code>([^、]+)([、]{1})</code> - Replace with: <code>\1\n</code>


<span id="replace-multiple-spaces-with-tab-characters"></span>
=== Replace Multiple Spaces with Tab Characters ===
=== Replace Multiple Spaces with Tab Characters ===


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'''Using Sublime Text:''' - Find: <code>([^\S\n]+)</code> or <code>([^\S\r\n]+)</code> or <code>\s\s+</code> - Replace with: <code>\t</code>
'''Using Sublime Text:''' - Find: <code>([^\S\n]+)</code> or <code>([^\S\r\n]+)</code> or <code>\s\s+</code> - Replace with: <code>\t</code>


<span id="remove-leadingtrailing-whitespace"></span>
 
=== Remove Leading/Trailing Whitespace ===
=== Remove Leading/Trailing Whitespace ===


<span id="remove-leading-whitespace"></span>
 
==== Remove Leading Whitespace ====
==== Remove Leading Whitespace ====


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* Replace with: (empty)
* Replace with: (empty)


<span id="remove-trailing-whitespace"></span>
 
==== Remove Trailing Whitespace ====
==== Remove Trailing Whitespace ====


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* Replace with: (empty)
* Replace with: (empty)


<span id="remove-both-leading-and-trailing-whitespace"></span>
 
==== Remove Both Leading and Trailing Whitespace ====
==== Remove Both Leading and Trailing Whitespace ====


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* Replace with: (empty)
* Replace with: (empty)


<span id="text-editors-supporting-regular-expressions"></span>
 
== Text Editors Supporting Regular Expressions ==
== Text Editors Supporting Regular Expressions ==


Various text editors support regular expressions including: - Sublime Text - EmEditor - Notepad++ - Visual Studio Code - Atom - Vim/Neovim
Various text editors support regular expressions including: - Sublime Text - EmEditor - Notepad++ - Visual Studio Code - Atom - Vim/Neovim


<span id="syntax-reference"></span>
 
== Syntax Reference ==
== Syntax Reference ==


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* Non-whitespace: <code>\S</code> - Does not include half-width spaces and full-width spaces
* Non-whitespace: <code>\S</code> - Does not include half-width spaces and full-width spaces


<span id="troubleshooting-regular-expressions"></span>
== Troubleshooting Regular Expressions ==
== Troubleshooting Regular Expressions ==


'''Tips:''' 1. Use online tools like regex101 to understand your syntax 2. Test with small data: Prepare small file data to verify syntax 3. Highlight or output matched text for debugging 4. Simplify the syntax when encountering issues 5. Try alternative syntax due to compatibility issues (e.g., <code>\d</code> to <code>[0-9]+</code>)
'''Tips:''' 1. Use online tools like regex101 to understand your syntax 2. Test with small data: Prepare small file data to verify syntax 3. Highlight or output matched text for debugging 4. Simplify the syntax when encountering issues 5. Try alternative syntax due to compatibility issues (e.g., <code>\d</code> to <code>[0-9]+</code>)


<span id="alternative-solutions"></span>
 
== Alternative Solutions ==
== Alternative Solutions ==


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* Copy multiple rows and paste between different applications (compatibility varies)
* Copy multiple rows and paste between different applications (compatibility varies)


<span id="further-reading"></span>
== Further Reading ==
== Further Reading ==


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* Platform-specific regular expression documentation
* Platform-specific regular expression documentation


{{Template:Data factory flow}}
{{Template: Data factory flow}}


[[Category: Regular expression]]  
[[Category: Regular expression]]  

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