array [
y => 35
x => 51
z => 35
c_3 => 4
c_1 => 54
c_6 => 53
c_9 => 52
]
我想获得数组：
array [c_3=>4, c_1=>54, c_6=>53, c_9=>52]
如何过滤掉没有以 c_ 开头的元素？
试试这个：
$filtred = array();
foreach($yourArray as $key => $value)
if(preg_match('/c_\d/',$key))
$filtred[] = $value;
print_r($filtred);
试一下这个
//your array
$arr1 = array (
"y" => 35,
"x" => 51,
"z" => 35,
"c_3" => 4,
"c_1" => 54,
"c_6" => 53,
"c_9" => 52
);
// Array with keys you want
$arr2 = array (
"c_3" => '',
"c_1" => '',
"c_6" => '',
"c_9" => ''
);
//use array_intersect_key to find the common ;)
print_r(array_intersect_key($arr1,$arr2));
使用array_filter()检查此解决方案
$arr = [
'y' => 35,
'x' => 51,
'z' => 35,
'c_3' => 4,
'c_1' => 54,
'c_6' => 53,
'c_9' => 52,
];
$filtered = array_filter($arr, function($v) use($arr){
return preg_match('#c_\d#', array_search($v, $arr));
});
$filtered = array_filter($arr, function($k){
return preg_match('#c_\d#', $k);
}, ARRAY_FILTER_USE_KEY);
这两种解决方案都有效，我已经检查过了。
preg_match('#c_\d#', array_search($v, $arr)) 是一个不好的想法。看看它失败了：演示。原因是因为 array_search() 返回第一个匹配值的键。这在任何脚本中都不应该被使用。 - mickmackusa我尝试了上面的解决方案，但是在PHP 5.6中都没有起作用。
因此，我尝试并使用了不同的解决方案，这对我有用...
注：Original Answer翻译成"最初的回答"$subArray = array();
foreach($arryDetails as $key => $value)
if(preg_match('/^c_/',$key))
$subArray[$key] = $value;
print_r($subArray);
array_slice()对于此任务没有任何好处。链接的页面也不相关--它演示了完整键过滤，而这个问题是根据部分键匹配进行过滤。 - mickmackusa我之前也有类似的问题，并在这里寻找答案，但没有什么能满足我的期望。
我想要一个更可重用的解决方案，可以在所有项目中使用，所以最终我写了这个函数:
/**
* Create a new a array containing only the key with a certain $pattern or $subString.
*
* Note: You cannot use both $subString and $pattern at once ($substring has precedence on $pattern).
*
* @param $errorMessage String to return the error message.
* @param $source Array in which we must extract data.
* @param $subString String/Int/Array substring (or array of substring) to seek in the key name.
* @param $pattern String regex for validating the key.
* @param $useValueAsKey Boolean if true it will use the value as the key in the new array (scalar values only).
*/
public static function extractSubArray(&$errorMessage, array &$source, $subString ="", $pattern = "", $useValueAsKey=false){
$newArray = array();
$errorMessage = "";
$dbManager = GeneralDbManager::getInstance();
if (empty($source)){
$errorMessage = $dbManager->getErrorMessage("SOURCE_ARRAY_IS_EMPTY_ERR", "The array supplied is empty.");
}
elseif(empty($subString) and empty($pattern)){
$errorMessage = $dbManager->getErrorMessage("NO_SUBSTR_OR_PATTERN_ERR", "There are no substring or pattern to match the keys in the array.");
}
elseif (!empty($subString) and !(is_string($subString) or is_numeric($subString) or is_array($subString))){
$errorMessage = $dbManager->getErrorMessage("INVALID_MATCH_SUBSTRING_ERR", "The substring you supplied to match the keys is invalid.");
}
elseif(!empty($pattern) and !RegularExpression::testRegex($pattern)){
$errorMessage = $dbManager->getErrorMessage("INVALID_MATCH_PATTERN_ERR", "The regular expression you supplied to match the keys is invalid.");
}
else{
foreach ($source as $key => $value){
if (self::isKeyMatchSubstring($key, $subString, $pattern)){
if ($useValueAsKey and (is_string($value) or is_numeric($value))){
$newArray[$value] = $value;
}
else{
$newArray[$key] = $value;
}
}
}
if (empty($newArray)){
$errorMessage = $dbManager->getErrorMessage("INVALID_MATCH_PATTERN_ERR", "We were not able to match any keys in the array with the substring or the regular expression.");
}
}
unset($dbManager);
return $newArray;
}
/**
* Validate that the $key contains the $substring (string or array) or match the $pattern.
*
* @param $key String to validate
* @param $subString String/Int/Array containing the subString to seek.
* @param $pattern String regex for validating the key.
*/
private static function isKeyMatchSubstring($key, $subString, $pattern){
$matched = false;
if (!empty($subString)){
if (is_string($subString) or is_numeric($subString)){
if(strpos(strtolower($key), strtolower($subString)) !== false){
$matched = true;
}
}
else{ //array
foreach($subString as $testString){
$matched = self::isKeyMatchSubstring($key, $testString, "");
if ($matched){
break;
}
}
}
}
elseif(!empty($pattern)){
$matched = preg_match($pattern, $key);
}
return $matched;
}
它使用一个名为testRegex()的函数，所以我想我也可以提供那段代码：
/**
* Make sure that a regular expression works in PHP.
*
* @param $regex String the regular expression to validate.
*
* @return Boolean
*/
public static function testRegex($regex){
$isValid = false;
if (!empty($regex) and is_string($regex)){
if (@preg_match($regex, null) !== false){
$isValid = true;
}
}
return $isValid;
}
当然，没有单元测试的函数有多好呢？
public function testExtractSubArray(){
$errorMessage = "";
$source = array();
//no data
$this->assertEmpty(Tool::extractSubArray($errorMessage, $source, "", "", false));
$this->assertNotEmpty($errorMessage);
//no substring or pattern
$source = array(1 => 1);
$this->assertEmpty(Tool::extractSubArray($errorMessage, $source, "", "", false));
$this->assertNotEmpty($errorMessage);
//invalid substring
$dbmanager = GeneralDbManager::getInstance();
$this->assertEmpty(Tool::extractSubArray($errorMessage, $source, $dbmanager, "", false));
$this->assertNotEmpty($errorMessage);
unset($dbmanager);
//invalid pattern
$this->assertEmpty(Tool::extractSubArray($errorMessage, $source, "", "[]123", false));
$this->assertNotEmpty($errorMessage);
//no match
$this->assertEmpty(Tool::extractSubArray($errorMessage, $source, "pokemon", "", false));
$this->assertNotEmpty($errorMessage);
//valid substring
$source = array("woot1" => "homer", "woot2" => "bart", "woot3" => "lisa", "doh1" => "marge", "doh2" => "simpson");
$newArray = Tool::extractSubArray($errorMessage, $source, "WOOT", "", false);
$this->assertNotEmpty($newArray);
$this->assertEmpty($errorMessage);
$this->assertContains("homer", $newArray);
$this->assertContains("bart", $newArray);
$this->assertContains("lisa", $newArray);
$this->assertNotContains("marge", $newArray);
$this->assertNotContains("simpson", $newArray);
//use value as key
$newArray = Tool::extractSubArray($errorMessage, $source, "WOOT", "", true);
$this->assertTrue(array_key_exists("homer", $newArray));
$this->assertTrue(array_key_exists("bart", $newArray));
$this->assertTrue(array_key_exists("lisa", $newArray));
//substring array
$source = array("stan_march" => "normal", "kyle_brofloski" => "jew", "eric_cartman" => "asshole", "kenny_mccormick" => "dead", "butters_stotch" => "pushover");
$newArray = Tool::extractSubArray($errorMessage, $source, array("stan", "kyle", "cartman"), "", false);
$this->assertNotEmpty($newArray);
$this->assertEmpty($errorMessage);
$this->assertContains("normal", $newArray);
$this->assertContains("jew", $newArray);
$this->assertContains("asshole", $newArray);
$this->assertNotContains("dead", $newArray);
$this->assertNotContains("pushover", $newArray);
//regex
$source = array("jonathan@woot.ca" => 1, "jonathan" => 2, "12345" => 3, "more $$$" => 4, "$?%$?%$%?" => 5);
$newArray = Tool::extractSubArray($errorMessage, $source, "", RegularExpression::ALPHA_NUMERIC, false);
$this->assertNotEmpty($newArray);
$this->assertEmpty($errorMessage);
$this->assertNotContains(1, $newArray);
$this->assertContains(2, $newArray);
$this->assertContains(3, $newArray);
$this->assertNotContains(4, $newArray);
$this->assertNotContains(5, $newArray);
}
附加说明：此代码使用getErrorMessage()方法从数据库中获取错误消息的翻译。由于这些错误消息是为了调试目的而设计的，因此可以直接在代码中进行硬编码以提高性能（无需实例化类来获取错误消息并打开与数据库的连接）。