Let’s first look at a sql statement:
select * from table where ctime >= '[date-14]' and ctime <= '[date-1]';
I want to replace the dates represented by square brackets in the above SQL statement with the elements in the array below: array('2015-07-01','2015-07-15');
Use regular matching: find the first square bracket part, replace it with the first element, then find the second one, and replace it
Use sprintf function: Because the dates have been calculated, just replace them in order.
Because it is troublesome to write regular expressions in markdown, I will upload pictures directly here
ps: Imagine that if there is only one time condition in SQL that needs to be replaced, it needs to be modified to
$sql = sprintf($sql,$arr[0])
To put it bluntly, it would be great if the sprintf function supports the second parameter being an array. After some research, there is indeed a solution:
call_user_func_array() The official explanation is:
call_user_func_array — Call the callback function and pass an array parameter as the parameter of the callback function
mixed call_user_func_array ( callable $callback , array $param_arr )
Call the first parameter as the callback function (callback), and pass in the parameter array (param_arr) as the parameters of the callback function.
That is to say: the first parameter is the name of the function you want to use (sprintf above), and the second parameter is the parameter of the function to be used, but the parameters are passed to call_user_func_arrayok in the form of an array, so If so, dynamic replacement can be achieved
$param = $arr;
array_unshift($param,$sql);
$sql = call_user_func_array('sprintf',$param);Next, we will introduce str_replace — substring replacement, array replacement
Description
mixed str_replace ( mixed $search , mixed $replace , mixed $subject [, int &$count ] )
This function returns a string or array. This string or array is the result of replacing all search in subject with replace.
If you have some special replacement requirements (such as regular expressions), you should use this function to replace ereg_replace() and preg_replace().
Parameters
If search and replace are arrays, str_replace() will perform mapping replacement on subject. If the number of replace values is less than the number of search values, additional replacements will be performed using empty strings. If search is an array and replace is a string, then the replacement of each element in search will always use this string. This conversion does not change case.
If search and replace are both arrays, their values will be processed sequentially.
search
The target value to find, which is needle. An array can specify multiple targets.
replace
Replacement value for search. An array can be used to specify multiple replacements.
subject
Array or string to perform replacement. That is haystack.
If subject is an array, the replacement operation will traverse the entire subject and the return value will also be an array.
count
Note: If specified, it controls the number of matches and replacements.
Return value
This function returns the replaced array or string.
Version Description
5.0.0 adds count parameter.
4.3.3 Function behavior changes. There is a BUG in the old version - when both parameters of search and replace are arrays, the empty search index will be skipped, but the internal pointer of replace will not be advanced at the same time. This error occurs in PHP
4.3.3, any scripts that depend on this bug should first remove empty lookup values to simulate the original behavior.
4.0.5 Most parameters can be arrays.
Example
Example #1 str_replace() basic example
<?php
// 赋值: <body text='black'>
$bodytag = str_replace("%body%", "black", "<body text='%body%'>");
// 赋值: Hll Wrld f PHP
$vowels = array("a", "e", "i", "o", "u", "A", "E", "I", "O", "U");
$onlyconsonants = str_replace($vowels, "", "Hello World of PHP");
// 赋值: You should eat pizza, beer, and ice cream every day
$phrase = "You should eat fruits, vegetables, and fiber every day.";
$healthy = array("fruits", "vegetables", "fiber");
$yummy = array("pizza", "beer", "ice cream");
$newphrase = str_replace($healthy, $yummy, $phrase);
// 赋值: 2
$str = str_replace("ll", "", "good golly miss molly!", $count);
echo $count;
?>Example #2 Possible str_replace() replacement example
<?php
// 替换顺序
$str = "Line 1\nLine 2\rLine 3\r\nLine 4\n";
$order = array("\r\n", "\n", "\r");
$replace = '<br />';
// 首先替换 \r\n 字符，因此它们不会被两次转换
$newstr = str_replace($order, $replace, $str);
// 输出 F ，因为 A 被 B 替换，B 又被 C 替换，以此类推...
// 由于从左到右依次替换，最终 E 被 F 替换
$search = array('A', 'B', 'C', 'D', 'E');
$replace = array('B', 'C', 'D', 'E', 'F');
$subject = 'A';
echo str_replace($search, $replace, $subject);
// 输出: apearpearle pear
// 由于上面提到的原因
$letters = array('a', 'p');
$fruit = array('apple', 'pear');
$text = 'a p';
$output = str_replace($letters, $fruit, $text);
echo $output;
?>Notes
Note: This function is safe to use on binary objects.
Caution
Learn the substitution order
Since str_replace() is replaced from left to right, previously inserted values may be replaced when performing multiple replacements. See this document for examples.
Note:
This function is case-sensitive. Case-insensitive replacement is possible using str_ireplace().
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