Label: boost C RegEx short performance string
Yesterday, we summarized the performance of various regular expression matching libraries under the long target string and concluded that boost RegEx has the best performance. Today, I applied it to the project. Naturally, the performance loss caused by long string matching is basically lost. Of course, the current scale is not too large, however, boost can full
If you are familiar with SED, awk, grep, or VI in Linux, the concept of regular expressions is certainly not unfamiliar. Because it can greatly simplify the complexity of processing strings, it has been applied in many Linux utilities. Do not think that regular expressions are only patents for Perl, Python, Bash, and other scripting languages. As a C language programmer, users can also use regular expressions in their own programs.Standard C and C ++ do not support regular expressions, but some
As shown in the Reddit recommendation article. The followingCodeRun in the CMD window. If running in bash, single quotes and double quotation marks must be reversed.
Perl
-
Wle
"
Print 'prime 'if (1 X shift )!~ /^ 1? $ | ^ (11 + ?) \ 1 + $/
"
Any number
>
The Python code is:
Import
Re
Def
Is_prime (Num ):
Return
Not
Re. Match (R
"
^ 1? $ | ^ (11 + ?) \ 1 + $
"
,
"
1
"
*
Num)
Ruby has the blood of Perl, so the code is almost the same as
To use the RegEx class, you must reference the namespace: using system. Text. regularexpressions;
Verification using the RegEx class
Example 1: AnnotatedCodeThe role is the same, but one is static method and the other is instance method.
VaR source = "Liu Bei Guan Yu Zhang Fei Sun Quan ";// RegEx = new RegEx ("Su
A bit of confusion about the split (string regex) method for string classes in Java
This class is described in the JDK Chinese API as follows:
Public string[] split(String regex)
Splits this string according to the match of the given regular expression.
The method acts as if the two-parameter split method is invoked using the given expression and the constraint parameter 0来. Therefore, the trailing empty st
I. Overview
RegEx. Match Method
Search for matching items of the regular expression in the input string, and return the exact result as a single match object.
Reload list(1) Search for the regular expression match specified in the RegEx constructor in the specified input string.
[C #] public match (string );
(2) Search for regular expression matching items in the input string from the starting position of
I. Overview
RegEx. Match Method
Search for matching items of the regular expression in the input string, and return the exact result as a single match object.
Reload list(1) Search for the regular expression match specified in the RegEx constructor in the specified input string.
[C #] public match (string );
(2) Search for regular expression matching items in the input string from the starting
These two days in the demo. The function is implemented in a template (string Type, which is actually an SQL select query statement), and a regular expression is used to query fields that meet the conditions, then, replace other values with the actual available query statements and display them.
This is because you are not quite clear about what you need. So after a while, I figured out my thoughts.
The general implementation steps are as follows:
1. Because the template is in an arrayinfo, find
In the regex_search function, the first matching result found is saved to a Smatch class. However, if there are multiple matching results in the search string, you need to implement it yourself.In Smatch, there are two members, the official documents are as follows:Iterator First:An iterator denoting the position of the the match.Iterator secondAn iterator denoting the position of the end of the match.Therefore, the following method can be used to get a traversal search:[CPP]View Plaincopy
#
C # Regular Expression Regex class usage,
I. C # Regular Expression symbol Mode
Character
Description
\
Escape Character, escape a character with special functions into a common character, or vice versa
^
Match the start position of the input string
$
End position of matching input string
*
Matches the previous zero or multiple subexpressions.
+
Match the previous subexpression o
The ExtJS regex's validation attributes are in two cases, one is a red prompt box, and the other is a comment-like message that appears on the Tip box, but adds Ext.QuickTips.init () when the page is loaded, and the prompt box is displayed correctly.
Special Note: After the attribute regex to use/^ here Gazheng then $/the above regular expression wrapping up otherwise will report "the missing object";
Copy Code code as follows:
{
X
In the past-blogs, the topic mainly focus on the high query operation of MongoDB. In this blog, we simply study the regex expression in the mongdb. MongoDB also support the Regex query. For exampleThe expression is also able to combination with other expression.Notes:/^a/; /^a.*/; /^a.*$/has the same result, however the later, which has less efficiency than the first one. Because the later would scan all th
A new feature in ASP. NET 2.0 is it's built-in URL rewriting support. when I looked into this new feature I found out it lacked regular expressions support, wich is really the point of an URL mapper. scottglu at his blog, explains the reason why the ASP. net team didn't implemented this feature. basically they realized that a full featured version wocould want to take advantage of the next IIS 7.0 new features, specially the support for all content-types (images and directories ).
Anyway, it's
In this episode, Eric asks us to replace space count with spaces:
--------------------------------------------------------------------------------
Given a string with embedded space counts:
Replace the
So, if you have
You shoshould end up
Text
----------------------------------------------------------------------------------
And my answer is:
Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->Using system;
Using system. Collections. Generic;
Us
Difference between Python Xpath and Regex, pythonxpathregex
When crawling webpage information, we often need to use Regex or Xpath.Differences between the two:
RegexItself isText matching toolBecause it needs to be matched multiple times, it appliesShort and centralized information. It can be precisely matched and captured. HoweverLarge Capacity,Scattered contentHTML and other text, the efficiency will b
For example (,),., |, * and other symbols of the class: String area = "(30.13206313822174, 120.4156494140625) (29.87637380707133, 120.1629638671875) (29.882327547852515, 120.50079345703125)"; int t = area. split ("\\)"). length; System. out. println (t); public string [] split (string regex) the parameter name here is regex, that is, regular expression (regular expression ). This parameter is not a simple d
I. BACKGROUNDMany places in the project need to match strings, such as filtering filenames based on a specified filter string. First of all, I'm not familiar with the boost library; second, if a third-party library is introduced, it will increase the dependency of the library, and the consequence is that packaging a dynamic library or compiling it directly with a static library will increase the size of the program.In the beginning is to try to write their own fuzzy matching algorithm, very simp
When using the Javascrip regular expression, it is found that the contents of a particular string within a string can be taken according to a regular expression. To illustrate:functionCheck (email_address) {varRegex =/^ ([0-9a-za-z\-_\.] +) @ ([0-9a-z]+\. [A-z] {2,3} (\. [A-z] {2})?) $/G; if(Regex.test (email_address)) {varuser_name = Email_address.replace (Regex, "$" ); vardomain_name = Email_address.replace (Reg
In the so file using the regex in the Boost library, if the following error occurs:
Undefined symbol: _ZN5BOOST9RE_DETAIL14VERIFY_OPTIONSEJNS_15REGEX_CONSTANTS12_MATCH_FLAGSE
Note the absence of a source file referencing the regex when generating the so file requires that the Regex's library be added to the makefile or compiled and then recompiled
If the following compile error occurs when recompiling
R
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