What are the php type conversion functions?

In web development, we often need to convert different data types. For example, convert strings into integers and floating point numbers, convert dates into timestamps, etc. These conversion operations can be implemented in PHP through built-in functions. This article will introduce commonly used conversion functions in PHP.

1. Integer conversion function

1. intval(): Convert a variable to an integer type. When this function converts a string to an integer, it automatically ignores any non-numeric characters following the number.

Example:

$var = '123abc';
$intVar = intval($var);
echo $intVar; // 输出：123

2. floatval(): Convert a variable to a floating point type.

Example:

$floatVar = floatval('123.45');
echo $floatVar; // 输出：123.45

3. doubleval(): Alias ​​function of floatval(). It has the same function as floatval() and can convert a variable to a floating point type.

2. String conversion function

1. strval(): Convert a variable to string type.

Example:

$num = 123;
$str = strval($num);
echo $str;  // 输出：'123'

2. addslashes(): Add backslash "\" to the string, used to add escape characters in front of some special characters, such as Quotes, backslashes, etc.

Example:

$str = "I\'m studying PHP";
$str = addslashes($str);
echo $str; // 输出：I\'m studying PHP

3. stripslashes(): Removes the backslash "\". The function of this function is opposite to addslashes().

Example:

$str = "I\'m studying PHP";
$str = addslashes($str); // I\'m studying PHP
$str = stripslashes($str);
echo $str; // 输出：I'm studying PHP

3. Numeric formatting function

1. number_format(): Format a number into thousands separator format characters String, supports up to 4 parameters.

Example:

$num = 1234567.89;
$numStr = number_format($num, 2, '.', ','); // 参数1：数字；参数2：小数点后保留位数；参数3：小数点分隔符；参数4：千位分隔符
echo $numStr; // 输出：1,234,567.89

4. Date and time conversion function

1. strtotime(): Convert the date and time in string form into a timestamp. This function can receive a string representing a date and time and return the corresponding timestamp.

Example:

$timeStamp = strtotime('2020-11-11 12:30:00');
echo $timeStamp; // 输出：1605083400

2. date(): Convert a timestamp representing a date into date format. Various formats can be set.

Example:

$timeStamp = 1605083400;
$dateStr = date('Y-m-d H:i:s', $timeStamp);
echo $dateStr; // 输出：2020-11-11 12:30:00

To sum up, PHP provides many conversion functions that can convert different types of data. Developers can flexibly use these functions according to actual needs when writing code to achieve data type conversion.

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