Php string processing functions

Php string processing functions are very powerful in PHP processing strings, and there are a variety of methods, but sometimes you need to choose the simplest and ideal solution, this article lists 10 common cases of string processing in PHP and provides the most ideal processing method.

1. determine the length of a string

This is the most obvious example in the article. The question here is how to determine the length of a string. what we cannot but mention here is the strlen () function:

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

2. extract the text and create a summary.

News websites usually take a section about 200 characters and add a ellipsis at the end of the section to form a summary. in this case, you can use substr_replace () function to implement this function. for space reasons, only the limit of 40 characters 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. calculate the number of characters and words in a string.

I believe that you will often see blog or news articles to summarize the total number of words in the article, or we often see some requirements for contribution within a certain word range. at this time, you can use the str_word_count () function to calculate the total number of words in an article:

$ Article = "breaking news: In ultimate irony, man bites dog .";

$ WordCount = str_word_count ($ article); // $ wordCount = 8

Sometimes you need to strictly control the space used by the contributor, such as some comments. if you want to know how many characters to form an array, use the count_chars () function.

4. parse CSV files

Data is usually stored in a file (such as a known CSV file) in a comma separated form. the CSV file uses a comma or is similar to a predefined symbol, make each column of strings into a separate row. you may often create PHP scripts to import the data or parse what you need. over the years, I have also seen many methods for parsing CSV files. The most common method is to use 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 fopen () and fgetcsv () functions, we can easily parse this file and retrieve the name of each contact at the same time:

$ Fh = fopen ("contacts.csv", "r ");

While ($ line = fgetcsv ($ fh, 1000 ,","))

{Echo "Contact: {$ line [1]}";}

5. convert to a string array

In some cases, you may need to create CSV files and read them at the same time, which means you need to convert the strings separated by commas into data, if the data is first retrieved from the database, it may only provide you with an array. in this case, you can use the implode () function, convert these strings into an array:

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

6. convert the URL to a hyperlink

Currently, many WYSIWYG editors allow users to mark text, including hyperlinks. However, when content is displayed on a page, you can easily perform this process automatically, at the same time, ensure that you do not encounter any extra errors. to convert the URL to a hyperlink, you can use the preg_replace () function, which can search for a string by regular expression, the URL structure is defined as follows:

$ Url = "LanFengye, LLC (http://www.phpfensi.com )";

$ Url = preg_replace ("/http: // ([A-z0-9 ../-] +)/", "$0", $ url );

// $ Url = "LanFengye, LLC (http://www.phpfensi.com )"

7. remove HTML tags from a string

As a Web developer, one of the main tasks is to ensure that user input does not contain any dangerous characters. if so, this will lead to SQL injection or script attacks, PHP includes many security features that can help you filter data, including extended filters. for example, you can allow users to include some basic HTML statements, you can use the strip_tags () function with the check function to remove all HTML tags from the string by default, however, you can also overwrite the default or specified labels. for example, in the following example, you can remove all labels:

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

8. compare two strings

Compare two strings to make sure they are the same. for example, you can use the substr_compare () function to determine whether the password entered for the first and second times is the same:

$ Pswd = "secret ";

$ Pswd2 = "secret ";

If (! Strcmp ($ pswd, $ pswd2 ))

{Echo "The passwords are not identical! ";

}

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

9. line feed conversion

This article describes how to easily convert a URL to a hyperlink. now we will introduce the nl2br () function, which can help you convert any line break into an HTML tag.

$ Comment = nl2br ($ comment );

10. automatic application line feed

Automatically wrap the application. 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 and 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.

Addcslashes-add backslash escape characters to some characters in the string

Addslashes-escape characters in the string in the specified method

Bin2hex-Convert binary data to hexadecimal representation

Alias function of chop-rtrim ()

Chr-returns the ASCII code of a character.

Chunk_split-splits a string into small parts based on a certain character length

Convert_cyr_string-converts a Slavic character to another character

Convert_uudecode-decrypts a string

Convert_uuencode-encrypt a string

Count_chars-returns the character usage information in a string.

Crc32-calculate the crc32 polynomial of a string

Crypt-one-way hash encryption function

Echo-used to display some content

Explode-convert a string into an array using a delimiter

Fprintf-return data as required and directly write data to the document stream

Get_html_translation_table-returns the HTML entity that can be converted.

Hebrev-converts a Hebrew-encoded string to a visualized text

Hebrevc-convert Hebrew-encoded strings into visualized text

The inverse function of the html_entity_decode-htmlentities () function, which converts an HTML object to a character.

Htmlentities-convert some characters in a string to HTML entities

The inverse function of the htmlspecialchars_decode-htmlspecialchars () function, which converts an HTML object to a character.

Htmlspecialchars-convert some characters in a string to HTML entities

Implode-convert an array into a string using a specific delimiter

Join-convert an array into a string, alias of the implode () function

Levenshtein-calculate the differences between two words

Localeconv-get format definitions related to numbers

Ltrim-removes white spaces or specified characters on the left of the string

Md5_file-encrypt an object using the MD5 algorithm

Md5-encrypt a string using the MD5 algorithm

Metaphone-rules for determining the pronunciation of a string

Money_format-formatted output of numbers based on parameters

Nl_langinfo-query language and local information

Nl2br-replace the linefeed "n" in the string with "n"
"

Number_format-formatted output of numbers based on parameters

Ord-converts an ASCII code to a character

Parse_str-convert strings of certain formats into variables and values

Print-Used to output a separate value

Printf-display data as required

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

Quotemeta-escape certain characters

Rtrim-removes spaces or specified characters on the right of the string

Setlocale-set the local format of numbers, dates, and so on

Sha1_file-encrypt a file using the SHA1 algorithm

Sha1-encrypt a string using the SHA1 algorithm

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

Soundex-rules for determining the pronunciation of a string

Sprintf-return data as required, but do not output

Sscanf-you can format strings.

Str_ireplace-match and replace strings like the str_replace () function, but not case sensitive

Str_pad-pad both sides of the string

Str_repeat-repeated string combination

Str_replace-match and replace strings

Str_rot13-encrypt the string with ROT13

Str_shuffle-random sorting of characters in a string

Str_split-splits a string into an array based on the character spacing

Str_word_count-get the English word information in the string

Strcasecmp-compare the string size, case insensitive

Strchr-returns the alias of some strstr () functions of a string through comparison

Strcmp-compare the string size

Strcoll-compare the string size based on local settings

Strcspn-returns the value of consecutive non-matching lengths.

Strip_tags-remove HTML and PHP code from a string

Stripcslashes-returns the string processed by the addcslashes () function escape function.

Stripos-locate and return the position of the first matching item. the matching is case insensitive.

Stripslashes-returns the string that has been escaped by the implicit addslashes () function.

Stristr-returns the part of a string through comparison. the comparison is case insensitive.

Strlen-get the encoding length of a string

Strnatcasecmp-use the natural sorting method to compare the string size, case insensitive

Strnatcmp-use the natural sorting method to compare the string size

Strncasecmp-compare the size of the first N characters of a string, case insensitive

Strncmp-compare the size of the first N characters of a string

Strpbrk-returns the part of a string through comparison

Strpos-locate and return the position of the first matching item

Strrchr-returns the part of a string through comparison from the back to the back

Strrev-reverse sort all letters in the string

Strripos-search from the back and return the position of the first matching item. the matching is case insensitive.

Strrpos-search from the back and return the position of the first matching item

Strsps-matched and returned continuous length of characters

Strstr-returns the part of a string through comparison

Strtok-use a specified number of characters to separate strings

Strtolower-convert string to lowercase

Strtoupper-converts a string to uppercase

Strtr-replace string comparison

Substr_compare-comparison after string truncation

Substr_count-calculates the number of occurrences of a character segment in a string

Substr_replace-replace some characters in the string

Substr-truncates a string

Trim-removes spaces or specified characters on both sides of the string

Ucfirst-converts the first letter of the given string into uppercase letters.

Ucwords-converts the first letter of each English word of the given string into uppercase letters.

Vfprintf-return data as required and directly write data to the document stream

Vprintf-display data as required

Vsprintf-return data as required, but no output

Wordwrap-splits a string based on a certain character length