Summarize the php case conversion formula

When writing PHP programs, it is often necessary to perform case conversion operations on strings. The following are several commonly used case conversion functions:

1. strtoupper() – Convert all characters in the string to uppercase

Syntax: strtoupper( string $string)

Example:

$str = 'Hello World';
echo strtoupper($str);    // 输出 HELLO WORLD

2. strtolower() – Converts all characters in the string to lowercase

Syntax: strtolower(string $string)

Example:

$str = 'Hello World';
echo strtolower($str);    // 输出 hello world

3. ucfirst() – Convert the first letter of the string to uppercase

Syntax: ucfirst(string $string)

Example:

$str = 'hello world';
echo ucfirst($str);    // 输出 Hello world

4. ucwords() – Convert the first letter of each word in the string For uppercase

Syntax: ucwords(string $string)

Example:

$str = 'hello world';
echo ucwords($str);    // 输出 Hello World

These functions are very useful during program development, It can help us quickly deal with case problems in strings and improve the efficiency of writing code. In addition, PHP also supports other string conversion functions, such as:

1. mb_strtolower() – Converts all characters in the string to lowercase (MB function library supports multi-byte characters)

Syntax: mb_strtolower(string $string [, string $encoding = mb_internal_encoding() ])

2. mb_strtoupper() – Change the All characters are converted to uppercase (MB function library supports multi-byte characters)

Syntax: mb_strtoupper(string $string [, string $encoding = mb_internal_encoding() ])

In general, using these case conversion functions in PHP allows us to process strings more conveniently and improve the readability and maintainability of the code.

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