How can I replace multiple strings within a string without overlapping results? - php

I'm trying to create common masks from a string like so:
012abc.d+e_fg~hijk => 012{start}.d+{middle}_fg~{end}jk
replace:
$arrFromTo = array(
'st' => '{pre}',
'abc' => '{start}',
'e' => '{middle}',
'hi' => '{end}',
'dd' => '{post}'
);
Instead I keep overlapping replacements and get something like this instead (using a loop of str_replace's):
012{{pre}art}.d+{mi{post}le}_fg~{end}jk
Because the st is found in the already replaced {start} and dd is found in {middle}.
How would you replace the following?
$str = 'abc.d+e_fg~hijk';
echo replace_vars($str); // Desired output: 012{start}.d+{middle}_fg~{end}kJ

I might misunderstand, but you don't seem to need regex for the replacing. They're simple, literal replacements.
$from = '012abc.d+e_fg~hijk';
$arrFromTo = array(
'st' => '{pre}',
'abc' => '{start}',
'e' => '{middle}',
'hi' => '{end}',
'dd' => '{post}'
);
$to = strtr($from, $arrFromTo); // 012{start}.d+{middle}_fg~{end}jk
strtr() is awesome. It takes a very readable input and it doesn't re-replace like your problem in the loop.

You can use preg_replace like this:
$str = '012abc.d+e_fg~hijk';
$arrFromTo = array(
'st' => '{pre}',
'abc' => '{start}',
'e' => '{middle}',
'hi' => '{end}',
'dd' => '{post}'
);
$reArr=array();
foreach($arrFromTo as $k=>$v){
$reArr['/' . $k . '(?![^{}]*})/'] = $v;
}
echo preg_replace(array_keys($reArr), array_values($reArr), $str);
//=> 012{start}.d+{middle}_fg~{end}jk
Core of this regex is this negative lookaead: (?![^{}]*})
Which avoid matching keys of array if it is enclosed in {...} since all the replacements are enclosed in {...}.

This will search the string for each replacement in order. If it finds one, it will split the string, and search the remainder of the string for any other replacements.
$str = '012abc.d+e_fg~hijk';
$rep = array(
'st' => '{pre}',
'abc' => '{start}',
'e' => '{middle}',
'hi' => '{end}',
'dd' => '{post}'
);
$searched = '';
foreach ($rep as $key => $r) {
if (strpos($str, $key) !== false) {
$searched .= substr($str, 0, strpos($str, $key)) . $r;
$str = substr($str, strpos($str, $key) + strlen($key));
}
}
$searched .= $str;
echo $searched; //012{start}.d+{middle}_fg~{end}jk
It will search and find them in the order that you have specified.

Related

Replace variables from text with corresponding values

Let say I have the following string which I want to send as an email to a customer.
"Hello Mr/Mrs {{Name}}. You have subscribed for {{Service}} at {{Date}}."
And I have an array with the values that should be replaced
array(
'Name' => $customerName, //or string
'Service' => $serviceName, //or string
'Date' => '2015-06-06'
);
I can find all strings between {{..}} with this:
preg_match_all('/\{{(.*?)\}}/',$a,$match);
where $match is an array with values, But I need to replace every match with a corresponding value from an array with values
Note that the array with values contains a lot more values and the number of items in it or the keys sequence is not relevant to number of matches in string.
You can use preg_replace_callback and pass the array with the help of use to the callback function:
$s = "Hello Mr/Mrs {{Name}}. You have subscribed for {{Service}} at {{Date}} {{I_DONT_KNOW_IT}}.";
$arr = array(
'Name' => "customerName", //or string
'Service' => "serviceName", //or string
'Date' => '2015-06-06'
);
echo $res = preg_replace_callback('/{{(.*?)}}/', function($m) use ($arr) {
return isset($arr[$m[1]]) ? $arr[$m[1]] : $m[0]; // If the key is uknown, just use the match value
}, $s);
// => Hello Mr/Mrs customerName. You have subscribed for serviceName at 2015-06-06.
See IDEONE demo.
The $m[1] refers to what has been captured by the (.*?). I guess this pattern is sufficient for the current scenario (does not need unrolling as the strings it matches are relatively short).
You don't need to use a regex for that, you can do it with a simple replacement function if you change a little the array keys:
$corr = array(
'Name' => $customerName, //or string
'Service' => $serviceName, //or string
'Date' => '2015-06-06'
);
$new_keys = array_map(function($i) { return '{{' . $i . '}}';}, array_keys($corr));
$trans = array_combine($new_keys, $corr);
$result = strtr($yourstring, $trans);
Try
<?php
$str = "Hello Mr/Mrs {{Name}}. You have subscribed for {{Service}} at {{Date}}.";
$arr = array(
'Name' => 'some Cust', //or string
'Service' => 'Some Service', //or string
'Date' => '2015-06-06'
);
$replaceKeys = array_map(
function ($el) {
return "{{{$el}}}";
},
array_keys($arr)
);
$str = str_replace($replaceKeys, array_values($arr), $str);
echo $str;

How to get value from nested array using string

I have an array like this:
$temp = array( '123' => array( '456' => array( '789' => '0' ) ),
'abc' => array( 'def' => array( 'ghi' => 'jkl' ) )
);
I have a string like this:
$address = '123_456_789';
Can I get value of $temp['123']['456']['789'] using above array $temp and string $address?
Is there any way to achieve this and is it good practice to use it?
This is a simple function that accepts an array and a string address where the keys are separated by any defined delimiter. With this approach, we can use a for-loop to iterate to the desired depth of the array, as shown below.
<?php
function delimitArray($array, $address, $delimiter="_") {
$address = explode($delimiter, $address);
$num_args = count($address);
$val = $array;
for ( $i = 0; $i < $num_args; $i++ ) {
// every iteration brings us closer to the truth
$val = $val[$address[$i]];
}
return $val;
}
$temp = array("123"=>array("456"=>array("789"=>"hello world")));
$address = "123_456_789";
echo delimitArray($temp,$address,"_");
?>
Hello if string $address = '123_456_789'; is your case then you can use explode function to split the string by using some delimeter and you can output your value
<?php
$temp = array('123' => array('456' => array('789' => '0')),
'abc' => array('def' => array('ghi' => 'jkl')),
);
$address = '123_456_789';
$addr = explode("_", $address);
echo $temp[$addr[0]][$addr[1]][$addr[2]];
Using this array library you can easily get element value by either converting your string to array of keys using explode:
Arr::get($temp, explode('_', $address))
or replacing _ with . to take advantage of dot notation access
Arr::get($temp, str_replace('_', '.', $address))
Another benefit of using this method is that you can set default fallback value to return if element with given keys does not exists in array.

Why does php str_replace with multiple arrays give wrong result, but for loop gives correct result?

I'm trying to replace the characters (numbers and letters) in a string. When I try the "php" way, it gives the wrong result for some of the characters. Why?
PHP-WAY:
$find = array( "0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f" );
$replace = array( "a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p" );
$haystack = "a5c9a06bfacf5f12cf01ab3f202f6c78"
//This incorrectly returns: kpmjkkglpkmppplmmpklklnpmkmpgmhi
echo str_replace( $find, $replace, $haystack );
LOOP WAY:
$find = array( "0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f" );
$replace = array( "a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p" );
$haystack = "a5c9a06bfacf5f12cf01ab3f202f6c78"
//This correctly returns: kfmjkaglpkmpfpbcmpabkldpcacpgmhi
$newStr = "";
$chars = str_split( $haystack );
for ( $i = 0, $length = count( $chars ); $i < $length; $i++ )
{
$newStr .= $replace[ array_search( $chars[ $i ], $find ) ];
}
echo $newStr;
Why is the first one incorrect? Am I using it wrong?
Order of entries in your arrays.... str_replace() will process each array entry in the order they appear in your array, so if a '1' gets replaced with 'b', then that 'b' will subsequently get replaced with 'l'; use strtr() rather than str_replace() if you want to prevent that behaviour.
$find = array( "0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f" );
$replace = array( "a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p" );
$haystack = "a5c9a06bfacf5f12cf01ab3f202f6c78" ;
echo strtr($haystack, array_combine($find, $replace));
Your own code only does a single replace because it's looping against your string, not against the from/to arrays.
Just use strtr
$haystack = "a5c9a06bfacf5f12cf01ab3f202f6c78" ;
echo strtr($haystack, implode($find), implode($replace));
Or preg_replace_callback
$find = array_flip($find);
echo preg_replace_callback('/[a-f0-9]/', function ($v) use($replace, $find) {
return $replace[$find[$v[0]]];
}, $haystack);
Output
kfmjkaglpkmpfpbcmpabkldpcacpgmhi
As specified by #MarkBaker, the answer is that str_replace does not simply move forward in the string, but instead works like a recursive .replace(). Instead, use strtr (which is equivalent to Linux tr command:
$tr = array( "0" => "a","1" => "b","2" => "c","3" => "d","4" => "e","5" => "f","6" => "g","7" => "h","8" => "i","9" => "j","a" => "k","b" => "l","c" => "m","d" => "n","e" => "o","f" => "p" );
$haystack = "a5c9a06bfacf5f12cf01ab3f202f6c78"
echo strtr( $haystack, $tr );

Parse data into array

I'm creating a "quote database" for a TV show I'm a fan of, and I'm rewriting parts of it I don't particularly like. I came across my function to parse the data holding the quote and characters into an array that I can easily loop through and display. One of the features of the site is that you can have a single quote (one-liner) or a conversation between several characters. Right now I'm storing single quotes like this:
[charactername]This is my witty one-liner.
And conversations follow the same pattern:
[characternameone]How's the weather?
[characternametwo]Pretty good, actually.
And so on. Here's the aforementioned parsing function:
function parse_quote($text)
{
// Determine if it's a single or convo
if ( strpos($text, "\n") != false )
{
// Convo
// Let's explode into the separate characters/lines
$text = explode("\n", $text);
$convo = array();
// Parse each line into character and line
foreach ( $text as $part )
{
$character = substr($part, 1, strpos($part, ']') - 1);
$line = substr($part, strlen($character) + 2);
$convo[] = array(
'character' => $character,
'line' => $line
);
}
return array(
'type' => 'convo',
'quote' => $convo
);
}
else
{
// Single
// Parse line into character and line
return array(
'type' => 'single',
'quote' => array(
'character' => substr($text, 1, strpos($text, ']') - 1),
'line' => substr($text, strlen(substr($text, 1, strpos($text, ']') - 1)) + 2)
)
);
}
}
It works as expected, but I can't help but think there's a better way to do this. I'm horrible with regular expressions, which I assume would come in at least somewhat handy in this situation. Any advice, or improvements?
Personally, I would change your data storage method. It would be much easier to deal with a serialized or JSON encoded string.
Instead of
[characternameone]How's the weather?
[characternametwo]Pretty good, actually.
you would have
array(
[0] => {
'name' => "characternameone",
'quote' => "How's the weather?"
},
[1] => {
'name' => "characternametwo",
'quote' => "Pretty good, actually"
}
)
Then when you read it out, there isn't any parsing.
function display_quote($input)
{
for ($i=0, $n=count($input); $i<$n; $i++) {
$quote = $input[$i];
if ( $i > 0 ) echo "\n";
echo $quote['name'] . ': ' . $quote['quote'];
}
}
Instead of
$character = substr($part, 1, strpos($part, ']') - 1);
$line = substr($part, strlen($character) + 2);
$convo[] = array(
'character' => $character,
'line' => $line
);
you could try
preg_match('#\[([^\]]+)\](.*)#ism', $part, $match);
$convo[] = array(
'character' => $match[1],
'line' => $match[2]
);
HTH

str_replace() with associative array

You can use arrays with str_replace():
$array_from = array ('from1', 'from2');
$array_to = array ('to1', 'to2');
$text = str_replace ($array_from, $array_to, $text);
But what if you have associative array?
$array_from_to = array (
'from1' => 'to1';
'from2' => 'to2';
);
How can you use it with str_replace()?
Speed matters - array is big enough.
$text = strtr($text, $array_from_to)
By the way, that is still a one dimensional "array."
$array_from_to = array (
'from1' => 'to1',
'from2' => 'to2'
);
$text = str_replace(array_keys($array_from_to), $array_from_to, $text);
The to field will ignore the keys in your array. The key function here is array_keys.
$text='yadav+RAHUL(from2';
$array_from_to = array('+' => 'Z1',
'-' => 'Z2',
'&' => 'Z3',
'&&' => 'Z4',
'||' => 'Z5',
'!' => 'Z6',
'(' => 'Z7',
')' => 'Z8',
'[' => 'Z9',
']' => 'Zx1',
'^' => 'Zx2',
'"' => 'Zx3',
'*' => 'Zx4',
'~' => 'Zx5',
'?' => 'Zx6',
':' => 'Zx7',
"'" => 'Zx8');
$text = strtr($text,$array_from_to);
echo $text;
//output is
yadavZ1RAHULZ7from2
$search = array('{user}', '{site}');
$replace = array('Qiao', 'stackoverflow');
$subject = 'Hello {user}, welcome to {site}.';
echo str_replace ($search, $replace, $subject);
Results in Hello Qiao, welcome to stackoverflow..
$array_from_to = array (
'from1' => 'to1',
'from2' => 'to2',
);
This is not a two-dimensional array, it's an associative array.
Expanding on the first example, where we place the $search as the keys of the array, and the $replace as it's values, the code would look like this.
$searchAndReplace = array(
'{user}' => 'Qiao',
'{site}' => 'stackoverflow'
);
$search = array_keys($searchAndReplace);
$replace = array_value($searchAndReplace);
# Our subject is the same as our first example.
echo str_replace ($search, $replace, $subject);
Results in Hello Qiao, welcome to stackoverflow..
$keys = array_keys($array);
$values = array_values($array);
$text = str_replace($key, $values, $string);

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