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IS 1181 IS 118 Introduction to Development Tools Chapter 4 String Manipulation and Regular Expressions.

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Presentation on theme: "IS 1181 IS 118 Introduction to Development Tools Chapter 4 String Manipulation and Regular Expressions."— Presentation transcript:

1 IS 1181 IS 118 Introduction to Development Tools Chapter 4 String Manipulation and Regular Expressions

2 IS 1182 Things to Cover Formatting strings Joining and splitting strings Comparing strings Matching and replacing substrings Using regular expressions This will be done using a Smart Form…

3 IS 1183 Listing 4.1 <?php //create short variable names $name=$_POST['name']; $email=$_POST['email']; $feedback=$_POST['feedback']; $toaddress = ''; $subject = 'Feedback from web site'; $mailcontent = 'Customer name: '.$name."\n".'Customer email: '.$email."\n"."Customer comments: \n".$feedback."\n"; $fromaddress = 'From:'; mail($toaddress, $subject, $mailcontent, $fromaddress); ?> Bob's Auto Parts - Feedback Submitted Feedback submitted Your feedback has been sent.

4 IS 1184 Listing facts Normally would check that all fields are filled – this does not! It also assumes that all fields are okay without extra spaces – Not good Uses mail function which is:  Bool mail (string to, sy=tring subject, string message, string [addit headers], string [addit parms])

5 IS 1185 A look at the code $mail content concatenates the customer name, email and comments into a single string This leads us to formatting strings Trimming:  trim () – strips off white space from beginning and end  Ltrim () and rtrim () – strips off white spaces from the left or the right.

6 IS 1186 More Formatting Converting text to HTML  nl2br () changes new lines to  sprintf returns a formatted string  printf () sends a formatted string to the browser  General format is (string format [, mixed args…])  See table 4.1 for conversion codes  Ex: printf(“total amount of order is %.2f (with shipping %.2f) “, $total, $total_Shipping) %.2f is format symbol (%), 2 decimals floating point

7 IS 1187 More Formatting Changing case  Srtrtoupper ($subject) changes to uppercase  Strtolower ($subject) to lower case  ucfirst ($subject) first letter to uppercase  Uwords( $subject) first letter of each word to uppercase  Addslashes() and stripsslashes() to take out or add slashes – often for database work

8 IS 1188 Joining and splitting strings explode (string separator, string input)  Splits up the input string into pieces based on the separator. explode(‘@’, $email) separates an email address into two parts strtok (string input, string separator) Splits up input string into pieces but one piece at a time $token = strtok($feedback, ‘ ‘); While ($token !=‘’) { $token – strtok(‘ ‘); echo $token.’ ’; };

9 IS 1189 More strings functions Substr ( string string, int start[, int length]);  Substr($test, 0, 4); Returns the first four characters Finding strings  strstr(), strchr(), strrchr() strstr( string haystack, string needle)  Strpos (), strrpos() – similar to strstr() Replacing strings  str_replace(), substr_replace() $feedback = str_replace($offcolor, ‘%!@*’, $feedback);

10 IS 11810 Regular Expressions When you want to do more than simple matches done so far we use regular expressions  It describes a pattern in a piece of text  It can use wildcards, (.) to match to a single => cat, sat, mat, #at would all match  Can control the matching [a-z]at says match any lowercase letter [a-zA-Z] says match any lower or upper case letter [^a-z]at means anything BUT lowercase a-z

11 IS 11811 Pre-defined character classes – p122  [[:alnum:]] Alphanumeric  [[:alpha:]] Alpha only  [[:lower:]] Lower case  [[:upper:]] Upper case  [[:digit:]] Decimal digits  [[:xdigit]] Hexadecimal digits  [[:punct:]] Punctuation  [[:blank:]] Tabs and spaces  [[:space:]] White space characters

12 IS 11812 Other Repetition: [[:alpha:]]+ means at least one alpha character Sub-expressions: [very]*large matches Large, very large, very very large and more Counted Sub-expressions: [very](1, 3) very, very very, very very very Special characters see table 4.4

13 IS 11813 Putting it all together To check for a validly constructed email address (p125): ^[a-zA-Z0-9_\-.]+@[a-zA-Z0-9_\-.]+\.[a-zA-Z0-9_\-.]+$  Means start at the beginning and it must have at least one letter, number, underscore, hyphen or dot.  @ matches the @  [a-zA-Z0-9_\-.]+ matches then the first part of the host name  The. Matches.  [a-zA-Z0-9_\-.]+$ matches the rest of the name Regular expression are not as efficient as string expressions but are more flexible and powerful

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