Shulou(Shulou.com)06/03 Report--

I would like to share with you the case conversion functions in php. I believe most people don't know much about it, so share this article for your reference. I hope you will gain a lot after reading this article. Let's learn about it together.

Php converts case functions: 1, strtoupper (), can convert the string to uppercase; 2, strtolower (), can convert the string to lowercase; 3, ucfirst (); 4, lcfirst (); 5, ucwords (); 6, mb_strtoupper (), etc.

Operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

In Web development, there are a lot of data that need to be regular and convenient for administrators to manage. Therefore, it is necessary to unify the case of letters when storing some data. However, in order to make it convenient for users to enter, they are not deliberately required to enter uppercase or lowercase, but use program control to store input in uppercase or lowercase when storing data.

PHP provides us with a number of predefined functions, including functions for string case conversion, as shown in the following table:

Function name function strtoupper converts a string to uppercase strtolower converts a string to lowercase ucfirst converts the first letter of a string to uppercase lcfirst converts the first letter of a string to lowercase ucwords converts the first character of each word in a string to uppercase mb_strtoupper converts a string to uppercase (unlike the strtoupper function) mb_strtolower converts a string to lowercase (unlike the strtolower function) mb_convert_case Convert strings according to different patterns

Next, let's introduce them separately.

1) strtoupper

The strtoupper () function converts letters in a string to uppercase, in the following syntax format:

Strtoupper ($string)

Where $string is a parameter of type string, and this function converts the letters in the parameter $string to uppercase and returns the converted string.

The sample code is as follows:

The running results are as follows:

HTTPS://WWW.PHP.CN/

2) mb_strtoupper

The function of the mb_strtoupper () function is similar to that of the strtoupper () function, which can also convert letters in a string to uppercase, and the mb_strtoupper () function can also set the character encoding of the parameter. The syntax format is as follows:

Mb_strtoupper ($str [, $encoding = mb_internal_encoding ()])

Where $str is the string to be converted and $encoding is an optional parameter that sets the character encoding of the parameter.

Unlike the strtoupper () function, the letters in $str are determined by the Unicode character attribute. So the mb_strtoupper () function is not affected by the locale (locale) setting and can convert any character with a "letter" attribute, such as a consonant (ä).

The sample code is as follows:

The running results are as follows:

3) strtolower

The strtolower () function converts letters in a string to lowercase in the following syntax format:

Strtolower ($string)

Where $string is a parameter of type string, and this function converts the letters in the parameter $string to lowercase and returns the converted string.

The sample code is as follows:

The running results are as follows:

Https://www.php.cn/

4) mb_strtolower

The function of the mb_strtolower () function is similar to the strtolower () function, which can also convert letters in a string to lowercase, and the mb_strtolower () function can also set the character encoding of the parameter. The syntax format is as follows:

Mb_strtolower ($str [, $encoding = mb_internal_encoding ()])

Where $str is the string to be converted and $encoding is an optional parameter that sets the character encoding of the parameter.

Unlike the strtolower () function, the detection of alphabetic characters in $str is based on the character's Unicode attribute. Therefore, the behavior of the function is not affected by the language setting and can convert any character with a "letter" attribute, such as the vowel consonant A.

The sample code is as follows:

The running results are as follows:

5) ucfirst

The ucfirst function converts the first letter of a string to uppercase. The syntax format is as follows:

Ucfirst ($str)

Where $str is the string to be converted.

The sample code is as follows:

The running results are as follows:

Hello world!Hello world!

6) lcfirst

The lcfirst () function can lowercase the first character of a string in the following syntax format:

Lcfirst ($str)

Where $str is the string to be converted.

The sample code is as follows:

The running results are as follows:

Hello World!hELLO WORLD!

7) ucwords

The ucwords () function converts the first letter of each word in a string to uppercase, in the following syntax format:

Ucwords ($str)

Where $str is the string to be converted, and $delimiters is an optional parameter to represent the word separator. The default is space character, tab character, line feed character, carriage return character, horizontal line, and vertical bar.

The sample code is as follows:

The running results are as follows:

Hello World!Hello World!

8) mb_convert_case

The mb_convert_case () function can convert the case of a string. The syntax format is as follows:

Mb_convert_case ($str, $mode [, $encoding = mb_internal_encoding ()])

Where $str is the string to be converted; $mode is the conversion pattern, which can be one of MB_CASE_UPPER, MB_CASE_LOWER, and MB_CASE_TITLE; and $encoding is the character encoding of the parameter, which can be omitted.

Compared with the strtolower () and strtoupper () functions, the case conversion of the mb_convert_case () function is performed on the basis of the Unicode character attribute. Therefore, the behavior of the mb_convert_case () function is not affected by the locale (locale) setting, and can convert any character with a "letter" attribute, such as the vowel consonant A (of).

The sample code is as follows:

The running results are as follows:

These are all the contents of this article entitled "what are the case conversion functions in php?" Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.