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SEARCH KEYWORD -- string format

  Output control functions in PHP

The Output Control functions in PHP allow you to control when output is sent from the script. This can be useful in several different situations, especially if you need to send headers to the browser after your script has began outputting data. The Output Control functions do not affect headers sent using header() or setcookie(), only functions such as echo and data between blocks of PHP code. These output control functions include ob_start(0, ob_clean(),ob_get_contents(), etc. To be honest, I a...

   PHP,output buffer,relationship,ob     2012-06-15 10:11:58

  Creating Dynamic PDF files using HTML and PHP

There always arise a need for converting content from one file format to another one. Some may need to convert some text into HTML and some may need to convert some HTML content to an image format. The main reason for the need to convert from one file format to another is because the target file format is best suited for targeted medium where the content need to be displayed. The targeted medium may be an email, a printed hard copy or a web browser. The text format is best suited for sending ema...

   PHP,HTML,PDF,Conversion,Generate,Library     2011-11-18 12:10:53

  Different types of keystore in Java -- DKS

Domain KeyStore(DKS) is a keystore of keystore. It abstracts a collection of keystores that are presented as a single logical keystore. Itself is actually not a keystore. This new keystore type is introduced in Java 8. There is a new class DomainLoadStoreParameter which closely relates to DKS. To load different keystores into the single logical keystore, some configuration is needed. Here is the format of the configuration for grouping different keystores. domain [ ...] { keystore [ ....

   Java,keystore,DKS,tutorial     2015-01-20 02:27:27

  Why exception would be thrown when deleting element while looping through HashMap in Java

HashMap and other Collection types are frequently used in Java application programming. This post will explain why exception would be thrown when deleting element with Map.remove() while looping through a Map using Iterator. This issue would also occur to other Collection types such as Set, List. Below is a sample code snippet demonstrating the exception thrown. Map<String,String> map = Collections.synchronizedMap(new TreeMap<String,String>()); map.put("key1","value1"); map.put("ke...

   JAVA,HASHMAP,CONCURRENTMODIFICATIONEXCEPTION     2018-06-30 12:49:09

  A Perl Regular Expression That Matches Prime Numbers

perl -lne '(1x$_) =~ /^1?$|^(11+?)\1+$/ || print "$_ is prime"' Can you figure out how it works? I give an explanation below, but try to figure it out yourself. Here is what happens when you run it: $ perl -lne '(1x$_) =~ /^1?$|^(11+?)\1+$/ || print "$_ is prime"' 1 2 2 is prime 3 3 is prime 4 5 5 is prime 6 7 7 is prime 8 9 10 11 11 is prime Here is how it works. First, the number is converted in its unary representation by (1x$_). For example, the number 5 gets converted into 1x5, which is ...

   Perl,Regex,Regular expression,Prime number,One line     2011-12-26 08:42:00

  Scala Macros

This is the home page of project Kepler, an ongoing effort towards bringing compile-time metaprogramming to Scala. Our flavor of macros is reminiscent of Lisp macros, adapted to incorporate type safety and rich syntax. Unlike infamous C/C++ preprocessor macros, Scala macros: 1) are written in full-fledged Scala, 2) work with expression trees, not with raw strings, 3) cannot change syntax of Scala. You can learn more about our vision of metaprogramming from our talks. We propose to enrich Scala ...

   Scala,Macro,Efficiency,Maintainebility     2012-02-01 00:12:15

  Fastjson just fixed a bug which might cause out of memory issue

Fastjson just fixed a bug which might cause service down a few days ago. This bug is caused by some mishandling of special character \x which is an escaped character to indicate hexdecimal number. The impact of this bug would be big if the attacker constructs a malicious data which would cause the service down.  The code which causes the issue is in com.alibaba.fastjson.parser.JSONLexerBase#scanString, when a JSON string is passed in, fastjson would parse the string character by c...

   FASTJSON,ALIBABA,BUG,NEWS     2019-09-07 06:03:49

  How regular expression works

Rob Pike wrote 30 lines of codes to realize a simple regular expression matcher in his book The practice of Programming. This piece of code is really cool. Let's take a look at the code.Meaning of different characters.Character Meaning c General character . Match any single character ^ Match start of a string $ Match end of a string * Match zero or many occurrences of a character /*match ：Test the regexp in text*/int match(char* regexp,char* text){    if(regexp[0] == '^')&n...

   Regular expression,Implementation,Rob Pike,C     2012-06-25 05:23:41

  Tips for improving PHP efficiency

0. Using single quote to replace double quote to enclose string literal, this will be a bit faster. Because PHP engine will search variables in double quoted string. 1. If a method in class can be declared as static, then make it static, this will be 4 times faster. 2. $row["id"] is 7 times faster than $row[id] 3. echo is faster than print, and you should use multiple parameters instead of string concatenation, i.e use comma(,) instead of dot(.) to concatenate string. For example echo $str1,$str...

   PHP, efficiency, tips     2012-10-01 19:39:06

  Greedy and Nongreedy Matching in a Regular Expression

By default, pattern matching is greedy, which means that the matcher returns the longest match possible. For example, applying the pattern A.*c to AbcAbcA matches AbcAbc rather than the shorter Abc. To do nongreedy matching, a question mark must be added to the quantifier. For example, the pattern A.*?c will find the shortest match possible. COPY // Greedy quantifiers String match = find("A.*c", "AbcAbc"); // AbcAbc match = find("A.+", "AbcAbc"); // AbcAbc // Nongreedy quantifier...

   Regular expression,Pattern match,Greedy,     2011-08-09 12:42:28

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