Note: below I am only printing the parts from the sample scripts
on the exercise page that need to be modified.
1) if (!preg_match("/the /i", $line, $matches)) {
2) a) ) Retrieve lines that have a word of any length that starts with t and
ends with e.
/\bt\w*e\b/
Modify this so that the word has at least three characters.
/\bt\w+e\b/
b) Retrieve lines that start with a.
/^a/
Retrieve lines that start with a and end with n.
/^a.*n$/
c) Retrieve blank lines. Think of at least two ways of doing this.
if (preg_match("/^$/", $line, $matches)) {
or
if (!preg_match("/./", $line, $matches)) {
d) a word that starts with an upper case letter
/\b[A-Z]\w*/
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3) What is the difference between the following expressions?
b) !preg_match("/yes/"...) and /[^y][^e][^s]/
!preg_match matches lines that do not contain the string "yes".
/[^y][^e][^s]/ matches lines that contain three characters so that
the first one is not "y", the second one is not "e", and the third one
is not "s". Eg. "yes" or "yeS" or "yyy" are not matched, but
"YES" or "yes!" are matched (because "es!" does not equal "yes").
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6a) Replace all upper case letters A by lower case letters a;
$line = preg_replace("/A/", 'a', $line);
6b) Delete all words with more than 3 characters.
$line = preg_replace("/\b\w\w\w+\b/", '', $line);
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5) Write a replace statement that deletes all HTML mark-up from a file.
$line = preg_replace("/<.*>/", '', $line);
But this doesn't work if there are several tags in one line because
* is greedy. Better solution:
$line = preg_replace("/<.*?>/", '', $line);
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6) Print double characters within parenthesis "()". For example, replace
"arrived" by "a(rr)ived".
$line = preg_replace("/(.)\\1/", '(\1\1)', $line);
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7) Read the alice.txt file into an array. Chomp it. Using join concatenate
it into one string. Then split it into words (or sentences) and print it
one word (sentence) per line.
Displaying a file word by word
Results:
$word) {
echo "Line ",$word_num,": ",$word, "
\n";
}
?>
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8) Write a script that takes an HTML source file as input and prints it so
that a newline follows only "closing tags", i.e. tags that are of the
form .
Reformated HTML
Results:
)/", "\\1\n", $line);
echo $line;
?>