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The m Modifier in .NET Integrate pdf417 2d barcode in .NET The m Modifier

The m Modifier generate, create none none on none projects data matrix The m modifi none for none er is used to control the behavior of the $ and ^ anchor metacharacters. A string containing newlines will be treated as multiple lines. If the regular expression is anchored with the ^ metacharacter, and that pattern is found at the beginning of any one of the multiple lines, the match is successful.

Likewise, if the regular expression is anchored by the $ metacharacter (or \Z) at the end of any one of the multiple lines, and the pattern is found, it too will return a successful match. The m modifier has no effect with \A and \z..

Example 9.29. (The Script) none for none # Anchors and the m modifier 1 $_="Today is history.\nTomorrow will never be here.\n"; 2 print if /^Tomorrow/; # Embedded newline 3 4 5 6 7 8 $_="Today is history.

\nTomorrow will never be here.\n"; print if /\ATomorrow/; # Embedded newline $_="Today is history.\nTomorrow will never be here.

\n"; print if /^Tomorrow/m; $_="Today is history.\nTomorrow will never be here.\n"; print if /\ATomorrow/m;.

9 $_="Today is history.\nTomorrow will never be here.\n"; 10 print if /history\.

$/m; (Output) 6 Today is Tomorrow 10 Today is Tomorrow. history. will never be here. history. will never be here. Explanation 1. The $_ scalar is assigned a string with embedded newlines. 2. The ^ met acharacter anchors the search to the beginning of the line. Since the line does not begin with Tomorrow, the search fails and nothing is returned.

. 3. The $_ scalar is assigned a string with embedded newlines. 4. The \A as sertion matches only at the beginning of a string, no matter what. Since the string does not begin with Tomorrow, the search fails and nothing is returned.

. 5. The $_ scalar is assigned a string with embedded newlines. 6. The m mod ifier treats the string as multiple lines, each line ending with a newline. In this example, the ^ anchor matches at the beginning of any of these multiple lines.

The pattern /^Tomorrow/ is found in the second line.. 7. The $_ scalar is assigned a string with embedded newlines. 8. The \A as sertion matches only at the beginning of a string, no matter how many newlines are embedded, and the m modifier has no effect. Since Tomorrow is not found at the beginning of the string, nothing is matched.

. 9. The $_ scalar is assigned a string with embedded newlines. 10. The $ me tacharacter anchors the search to the end of a line. With the m modifier, embedded newlines create multiple lines.

The pattern /history\.$/ is found at the end of the first line. This will also work with the \Z assertion but not with \z.

. Alternation Alternation allows the regular expression to contain alternative patterns to be matched. For example, the regular expression /John. Karen Steve/ will match a line containing John or Karen or Steve. If Karen, John, or Steve are all on different lines, all lines are matched. Each of the alternative expressions is separated by a vertical bar (pipe symbol) and the expressions can consist of any number of characters, unlike the character class that matches for only one character; e.

g., /a. b. c/ is the same as [abc], whereas /ab de/ cannot be represented as [abde]. The pattern /ab de/ is eithe none for none r ab or de, whereas the class [abcd] represents only one character in the set, a, b, c, or d. Example 9.30.

. (The Script) # Alternation: this, that, and the other thing 1 while(<DATA>){ 2 print if /Steve Betty Jon/; } _ _D ATA_ _ Steve Blenheim Betty Boop Igor Chevsky Norma Cord Jonathan DeLoach Karen Evich (Output) 2 Steve Blenheim Betty Boop Jonathan DeLoach. Explanation 1. The speci al 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 pipe symbol, . , is used in the regular expression to match on a set of alternative patterns. If any of the patterns Steve, Betty, or Jon, are found, the match is successful..

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