A detailed explanation of PHP string handling functions

PHP's ability to handle strings is very powerful, and there are a variety of ways, but sometimes you need to choose one of the simplest and most ideal solutions, the article lists 10 common string processing cases in PHP, and provides the most appropriate processing method.

1. Determine the length of a string

This is the most obvious example of the article, where the question is how we can determine the length of a string, and here we cannot fail to mention the strlen () function:

$text = "Sunny Day"; $count = strlen ($text); $count = 9

2. Truncate the text and create a summary.

News-Nature sites usually intercept a paragraph about 200 words, and add ellipses at the end of the paragraph to form a summary, so you can use the Substr_replace () function to do this, and for space reasons, only the 40-character limit is shown here:

$article = "Breaking news:in ultimate irony, man bites dog.";

$summary = Substr_replace ($article, "...", 40);

$summary = "Breaking news:in ultimate irony, man bi ..."

3. Calculating the number of characters and words in a string

I believe you will often see some blog or news articles, to summarize the total number of words, or we often see some of the requirements of the submission, within a certain range of words, at this time, you can use the Str_word_count () function to calculate the sum of the words of the article:

$article = "Breaking news:in ultimate irony, man bites dog.";

$wordCount = Str_word_count ($article); $wordCount = 8

There are times when you need to be more tightly controlled by the contributors ' use of space, such as some annotations and so on, if you want to know how many characters make up an array, use the Count_chars () function.

4. Parse the CSV file

Data is usually stored in a comma-delimited format (such as a known CSV file), the CSV file uses a comma or similar to a predefined symbol, each column string is composed of a separate row, you may often create PHP scripts to import this data, or resolve what you need, over the years, I have also seen many ways to parse CSV files, most commonly using a combination of fgets () and explode () functions to read and parse files, however, the simplest method is to use a function to solve the problem, but it is not part of the PHP string processing library: Fgetcsv () function, using the fopen () and Fgetcsv () functions, we can easily parse the file and retrieve the name of each contact:

$fh = fopen ("Contacts.csv", "R");

while ($line = Fgetcsv ($fh, 1000, ","))

{echo "contact: {$line [1]}";}

5. Converting to a string array

At some point, you might need to create a CSV file and read it in those files, which means you need to convert those comma-delimited strings into data, and if that data was originally retrieved from the database, it would probably just provide you with an array, and you can use implode () function to convert these strings into an array:

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

6. Convert URLs to hyperlinks

Currently many WYSIWYG editors provide toolbars that allow users to tag text, including hyperlinks, but when content is rendered to a page, you can easily automate this process, while ensuring that you do not have additional errors that you want to convert to the URL of a hyperlink, you can use Preg_replace ( ) function, which can search for a string by regular expression and defines the structure of the URL:

$url = "Lanfengye, LLC (http://www.phpfensi.com)";

$url = Preg_replace ("/http://([a-z0-9./-]+)/", "$", $url);

$url = "Lanfengye, LLC (http://www.phpfensi.com)"

7. Removing HTML tags from a string

As a web developer, one of the main tasks is to ensure that user input does not contain dangerous characters, and if so, this can lead to SQL injection or scripting attacks, and the PHP language contains a lot of security features that can help you filter data, including extension filters, for example, You can allow the user to have some basic HTML statements, including some comments, to implement this function, you can use the function with check function: Strip_tags (), it is the default is to remove all the HTML tags from the string, but also allows to override the default or you specify the label, such as , in the following example, you can remove all the tags:

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

8. Comparison of two strings

Compare two strings to make sure they are the same, for example, to determine if the user first enters the same password as the second time, you can use the Substr_compare () function to easily reality:

$PSWD = "secret";

$PSWD 2 = "secret";

if (! strcmp ($PSWD, $pswd 2))

{echo "The passwords is not identical!";

}

If you want to determine that two strings are not case-sensitive, you can use the strcasecmp () function.

9. Convert newline characters

In this article I describe how to easily convert URLs to hyperlinks, and now introduce the NL2BR () function, which can help you convert any newline character into an HTML tag.

$comment = NL2BR ($comment);

10. Apply the Wrap line

Apply word wrap, you can use this function in PHP: WordWrap ():

$speech = "Four score and seven years ago we fathers brought forth,

Upon this continent, a new nation, conceived in Liberty,

and dedicated to the proposition, all men is created equal. ";

Echo WordWrap ($speech, 30); Execute the above code, the result is:

Four score and seven years ago we fathers brought forth, upon this continent, a new nation, conceived in Liberty, and ded Icated to the proposition, all men is created equal.

Addcslashes-adds a backslash escape character for some characters inside a string

addslashes-characters inside a string are escaped in the specified manner

bin2hex-converts binary data to hexadecimal notation

alias function for Chop-rtrim ()

chr-returns the ASCII code of a character

Chunk_split-divide a string into small pieces at a certain length of character

Convert_cyr_string-converting Slavic characters to other characters

convert_uudecode-decrypting a string

convert_uuencode-Encrypt a string

count_chars-returns the character usage information for a string

crc32-computes a crc32 polynomial of a string

crypt-one-way hash encryption function

Echo-used to display some content

Explode-converts a string into an array form with a separator

fprintf-returns data as required and writes directly to the document stream

Get_html_translation_table-returning HTML entities that can be converted

hebrev-converting Hebrew encoded strings to visual text

hebrevc-converting Hebrew encoded strings to visual text

Inverse of the html_entity_decode-htmlentities () function to convert HTML entities to characters

htmlentities-convert some characters in a string to HTML entities

Inverse of the htmlspecialchars_decode-htmlspecialchars () function to convert HTML entities to characters

htmlspecialchars-convert some characters in a string to HTML entities

implode-to convert an array to a string with a specific separator character

join-convert an array to a string, alias of the Implode () function

levenshtein-Calculate the difference size of two words

localeconv-getting a number-related format definition

ltrim-to remove whitespace to the left of a string or to a specified character

md5_file-a file for MD5 algorithm encryption

md5-a string for MD5 algorithm encryption

Metaphone-judging the pronunciation rules of a string

money_format-output of numbers formatted according to parameters

nl_langinfo-querying language and local information

nl2br-Replace the line break "n" in the string with "<br/>"

number_format-output of numbers formatted according to parameters

ord-converts an ASCII code to one character

parse_str-Convert a string of a certain format into a variable and a value

Print-used to output a single value

printf-data Display as required

Quoted_printable_decode-to encrypt a string into a 8-bit binary string

Quotemeta-to escape a number of specific characters

rtrim-remove whitespace to the right of a string or a specified character

setlocale-setting local formats for numbers, dates, and so on

sha1_file-a file for SHA1 algorithm encryption

Sha1-a string for SHA1 algorithm encryption

Similar_text-compares two strings and returns the number of similar characters that the system thinks

Soundex-judging the pronunciation rules of a string

The sprintf-returns the data as required, but does not output

sscanf-can format a string

str_ireplace-matches and replaces strings like the Str_replace () function, but is case insensitive

str_pad-padding on both sides of a string

str_repeat-repeating combinations of strings

str_replace-matching and replacing strings

str_rot13-string for ROT13 encryption processing

str_shuffle-random ordering of characters inside a string

str_split-splits a string into an array by character spacing

str_word_count-get the English word information inside the string

strcasecmp-size comparison of strings, case insensitive

Strchr-the alias of a partial strstr () function that returns a string by comparison

strcmp-size comparison of strings

strcoll– size comparison of strings based on local settings

strcspn-returns the value of a continuous non-matching length of characters

strip_tags-remove HTML and PHP code from a string

stripcslashes-inverse literal addcslashes () function escapes processed strings

Stripos-finds and returns the position of the first occurrence, matching is case-insensitive

stripslashes-inverse literal addslashes () function escapes processed strings

stristr-returns a portion of a string by comparison, case-insensitive compared

Strlen-gets the encoded length of a string

strnatcasecmp-the size comparison of strings using natural sorting, case-insensitive

strnatcmp-the size comparison of strings using the natural sort method

strncasecmp-size comparison of the first n characters of a string, case insensitive

strncmp-size comparison of the first n characters of a string

strpbrk-returns a portion of a string by comparison

strpos-Find and return the position of the first occurrence

strrchr-returns a part of a string by comparing it from backward to forward

strrev-all letters inside the string in reverse order

Strripos-finds and returns the position of the first match from the back, matching is case insensitive

strrpos– Find and return the position of the first match from behind

strspn-matches and returns the value of the character continuous occurrence length

strstr-returns a portion of a string by comparison

strtok-to split a string with a specified number of characters

strtolower-converting a string to lowercase

strtoupper– converting a string to uppercase

strtr-to string comparison substitution

Substr_compare-Comparison of strings after interception

substr_count-count occurrences of a character segment in a string

substr_replace-to replace part of a character in a string

substr-to intercept a string

trim-remove whitespace or specified characters on either side of a string

Ucfirst-converts the first letter of a given string to uppercase

ucwords-the first letter of each English word of the given string into uppercase

vfprintf-returns data as required and writes directly to the document stream

vprintf-data Display as required

The vsprintf-returns the data as required, but does not output

wordwrap-to divide a string by a certain character length

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