10 common string processing example codes in PHP_PHP tutorial

PHP has a very powerful ability to process strings, and there are various methods, but sometimes you need to choose the simplest and ideal solution. The article lists 10 common string processing cases in PHP and provides the corresponding most ideal processing methods.

1. Determine the length of a string

This is the most obvious example in the article. The question is how do we determine the length of a string. What we must mention here is the strlen() function:

$text = "sunny day"; $count = strlen($text); // $count = 9

2. Intercept the text and create a summary

News websites usually intercept a paragraph of about 200 words and add an ellipsis at the end of the paragraph to form a summary. At this time, you can use the substr_replace() function to achieve this function. Due to space reasons, only the 40-character limit is demonstrated here:

$article = "BREAKING NEWS: In ultimate irony, man bites dog."; $summary = substr_replace($article, "...", 40); // $summary = "BREAKING NEWS: In ultimate irony, man bi..."

3. Count the number of characters and words in the string

I believe you often see some blogs or news articles summarizing the total word count of the article, or we often see some submission requirements: within a certain word count range. At this time, you can use the str_word_count() function to calculate the total number of words in the article:

$article = "BREAKING NEWS: In ultimate irony, man bites dog."; $wordCount = str_word_count($article); // $wordCount = 8

Sometimes you need to more strictly control the space used by contributors, such as some comments, etc. If you want to know how many characters make up an array, use the count_chars() function.

4. Parse CSV files

Data is usually stored in a file in comma-delimited form (such as a known CSV file). CSV files use a comma or similar predefined symbols to form each column of strings into a separate row. You may often create PHP scripts to import this data, or parse out what you need. Over the years, I have seen many methods of parsing CSV files. The most common is to use a combination of fgets() and explode() functions. To read and parse the file, however, the easiest way to solve the problem is to use a function that is not part of PHP's string processing library: the fgetcsv() function. Using the fopen() and fgetcsv() functions, we can easily parse this file and retrieve the name of each contact:

$fh = fopen("contacts.csv", "r"); while($line = fgetcsv($fh, 1000, ",")) { echo "Contact: {$line[1]}"; }

5. Convert to a string array

Sometimes, you may need to create CSV files and read from these files at the same time, which means you need to convert those comma-separated strings into data. If the data was initially retrieved from a database, it would most likely only give you an array. At this time, you can use the implode() function to convert these strings into an array:

$csv = implode(",", $record);

6. Convert URL into hyperlink

Many WYSIWYG editors currently provide toolbars that allow users to mark text, including hyperlinks. However, you can easily automate this process while ensuring that you don't encounter additional errors when the content is rendered to the page. To convert a hyperlink URL, you can use the preg_replace() function, which searches for a string according to a regular expression and defines the structure of the URL:

$url = "W.J. Gilmore, LLC (http://www.bkjia.com)"; $url = preg_replace("/http://([A-z0-9./-]+)/" , "$0", $url); // $url = "W.J. Gilmore, LLC (http://www.bkjia.com)"

7. Remove HTML tags from a string

As a web developer, one of your main jobs is to ensure that user input does not contain dangerous characters, which, if present, could lead to SQL injection or scripting attacks. The PHP language contains many security features that can help you filter data, including extending filters. For example, you can allow users to have some basic HTML statements, including some comments. To achieve this function, you can use the check function: strip_tags(). It removes all HTML tags from the string by default, but also allows overriding the default or tags you specify. For example, in the following example, you can remove all tags:

$text = strip_tags($input, " ");

8. Compare two strings

Compares two strings to make sure they are the same. For example, to determine whether the password entered by the user for the first time and the second time is the same, you can use the substr_compare() function to easily realize this:

$pswd = "secret"; $pswd2 = "secret"; if (! strcmp($pswd, $pswd2)) { echo "The passwords are not identical!"; }

If you want to determine whether two strings are case-insensitive, you can use the strcasecmp() function.

9. Convert line breaks

In this article I introduced how to easily convert a URL into a hyperlink. Now I introduce the nl2br() function, which can help you convert any newline character into an HTML tag.

$comment = nl2br($comment);

10. Apply automatic word wrapping

To apply automatic word wrapping, you can use this function in PHP: wordwrap():

$speech = "Four score and seven years ago our fathers brought forth, upon this continent, a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal."; echo wordwrap($speech, 30);

Execute the above code, the result is:

Four score and seven years ago our fathers brought forth, upon this continent, a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal.

Original address: http://phpbuilder.com/columns/Jason_Gilmore060210.php3

Original title: 10 Easy Solutions for PHP String Manipulation

Author: W. Jason Gilmore