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Explanation in .NET Insert pdf417 2d barcode in .NET Explanation




How to generate, print barcode using .NET, Java sdk library control with example project source code free download:
Explanation using barcode maker for .net control to generate, create pdf417 2d barcode image in .net applications. QR Codes 1. The $_ scalar is assigned a string. 2. The : turns off capturing when a pattern is enclosed in parentheses. In this example, alternation is used to search for any of two patterns.

If the search is successful, the value of $_ is printed, but whichever pattern is found, it will not be captured and assigned to $1.. 3. Without the :, t .net vs 2010 pdf417 he value of $1 would be Tom, since it is the first pattern found.

: says "Don"t save the pattern when you find it." Nothing is saved and nothing is printed..

Metacharacters that Look Ahead and Behind Looking ahead and lo PDF-417 2d barcode for .NET oking behind in a string for a particular pattern gives you further control of a regular expression. With a positive look ahead, Perl looks forward or ahead in the string for a pattern ( =pattern) and if that pattern is found, will continue pattern matching on the regular expression.

A negative look ahead looks ahead to see if the pattern ( !pattern) is not there, and if it is not, finishes pattern matching.. With a positive look behind, Perl looks backward in the string for a pattern ( <=pattern) and if that pattern is found, will then continue pattern matching on the regular expression. A negative look behind looks behind in the string to see if a pattern ( <!pattern) is not there, and if it is not, finishes the matching..

Table 9.8. Look Arou pdf417 for .

NET nd Assertions Metacharacter /PATTERN( =pattern)/ /PATTERN( !pattern)/ ( <=pattern)/PATTERN/ ( <!pattern)/PATTERN/ Example 9.44..

(The Script) # A pos itive look ahead 1 $string="I love chocolate cake and chocolate ice cream."; 2 $string =~ s/chocolate( = ice)/vanilla/; 3 print "$string\n"; $string="Tomorrow night Tom Savage and Tommy Johnson will leave for vacation."; 5 $string =~ s/Tom( =my)/Jere/g; 6 print "$string\n"; (Output) 3 I love chocolate cake and vanilla ice cream.

6 Tomorrow night Tom Savage and Jeremy Johnson will leave for vacation. 4. What It Matches Positive look ahead Negative look ahead Positive look behind Negative look behind Explanation 1. The scalar $strin .NET pdf417 g contains chocolate twice; the word cake follows the first occurrence of chocolate, and the word ice follows the second occurrence.

. 2. This is an exampl e of a positive look ahead. The pattern chocolate is followed by ( =ice) meaning, if chocolate is found, look ahead ( =) and see if ice is the next pattern.

If ice is found just ahead of chocolate, the match is successful and chocolate will be replaced with vanilla.. 3. After the substitution on line 2, the new string is printed. 4. The scalar $string is assigned a string of text consisting of three words starting with Tom. 5. The pattern is ma barcode pdf417 for .NET tched if it contains Tom, only if Tom is followed by my.

If the positive look ahead is successful, then Tom will be replaced with Jere in the string.. 6. After the substit ution on line 5, the new string is printed. Tommy has been replaced with Jeremy.

. Example 9.45. (The Script) # A neg ative look ahead 1 while(<DATA>){ 2 print if/^\w+\s( ![BC])/; } _ _DATA_ _ Steve Blenheim Betty Boop Igor Chevsky Norma Cord Jon DeLoach Karen Evich (Output) Jon DeLoach Karen Evich. Explanation 1. The special DATA filehandle gets its input from the text after the _ _DATA_ _ token. The while loop is entered and the first line after the _ _DATA_ _ token is read in and assigned to $_.

Each time the loop is entered, the next line following _ _DATA_ _ is assigned to $_ until all the lines have been processed.. 2. The regular expre .NET pdf417 2d barcode ssion means: Search at the beginning of the line for one or more word characters (\w+), followed by a space (\s), and look ahead for any character that is not a B or C.

This is called a negative look ahead.. Example 9.46. (The Script) # A pos .net vs 2010 barcode pdf417 itive look behind 1 $string="I love chocolate cake, chocolate milk, and chocolate ice cream."; 2 $string =~ s/( <= chocolate) milk/ candy bars/; 3 print "$string\n"; 4 5 6 $string="I love coffee, I love tea, I love the boys and the boys love me.

"; $string =~ s/( <=the boys) love/ don"t like/; print "$string\n";. (Output) 3 I love ch ocolate cake, chocolate candy bars, and chocolate ice cream. 6 I love coffee, I love tea, I love the boys and the boys don"t like me..

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