PHP常见问题解答

## How to replace a word inside a string in PHP
## How to prepend a string in PHP
## How to append a string in PHP
## How to extract substring from a string in PHP
## How to compare two strings in PHP
## How to get current page URL in PHP
## How to create a string by joining the values of an array in PHP
## How to split a string into an array in PHP
## How to combine two strings in PHP
## How to convert a string to lowercase in PHP
## How to convert a string to uppercase in PHP
## How to convert the first letter of a string to uppercase in PHP
## How to convert special HTML entities back to characters in PHP
## How to remove white space from the beginning of a string in PHP
## How to remove white space from the end of a string in PHP
## How to create a new line in PHP
## How to find string length in PHP
## How to check whether a variable is set or not in PHP
## How to check whether a variable is empty in PHP
## How to check whether a variable is null in PHP
## How to reverse a string in PHP
## How to replace the part of a string with another string in PHP
## How to count how many times a substring occurs in a string in PHP
## How to count all elements in an array in PHP
## How to print or echo all the values of an array in PHP
## How to display array structure and values in PHP
## How to reverse the order of an array in PHP
## How to check if a value exists in an array in PHP
## How to check if a key exists in an array in PHP
## How to remove the last element from an array in PHP
## How to remove the first element from an array in PHP
## How to add elements to the beginning of an array in PHP
## How to add elements to the end of an array in PHP
## How to merge two or more arrays into one array in PHP
## How to sort an array values alphabetically in PHP
## How to remove duplicate values from an array in PHP
## How to randomize the order of an array in PHP
## How to compare two array values in PHP
## How to calculate the sum of values in an array in PHP
## How to remove empty values from an array in PHP
## How to populate dropdown list with array values in PHP
## How to get all the keys of an associative array in PHP
## How to get all the values from an associative array in PHP
## How to sort an associative array by key in PHP
## How to sort an associative array by value in PHP
## How to get single value from an array in PHP
## How to loop through multidimensional array in PHP
## How to delete an element from an array in PHP
## How to check if a string contains a specific word in PHP
## How to get the current date and time in PHP
## How to make a redirect in PHP
## How to strip all spaces out of a string in PHP
## How to get the current year using PHP
## How to convert a date from yyyy-mm-dd to dd-mm-yyyy format in PHP
## How to convert a string to a number in PHP
## How to get the first element of an array in PHP
## How to convert a date to timestamp in PHP
## How to add elements to an empty array in PHP
## How to convert an integer to a string in PHP
## How to delete PHP array element by value not key
## How to push both key and value into an array in PHP
## How to refresh a page periodically using PHP
## How to remove the last character from a string in PHP
## How to return JSON from a PHP script
## How to get PHP errors to display