Latte Filters

Filters are functions that change or format the data to a form we want. This is summary of the built-in filters which are available.

There are also escaping filters for HTML (escapeHtml and escapeHtmlComment), XML (escapeXml), JavaScript (escapeJs), CSS (escapeCss) and iCalendar (escapeICal), which Latte uses itself thanks to context-aware escaping and you do not need to write them.

Latte the src and href attributes checks automatically, so you almost don't need to use the checkUrl filter.

All built-in filters work with UTF‑8 encoded strings.

Usage

Latte allows calling filters by using the pipe sign notation (preceding space is allowed):

<h1>{$heading|upper}</h1>

Filters can be chained, in that case they apply in order from left to right:

<h1>{$heading|lower|capitalize}</h1>

Parameters are put after the filter name separated by colon or comma:

<h1>{$heading|truncate:20,''}</h1>

Filters can be applied on expression:

{var $name = ($title|upper) . ($subtitle|lower)}</h1>

Custom filters can be registered this way:

$latte = new Latte\Engine;
$latte->addFilter('shortify', fn(string $s, int $len = 10) => mb_substr($s, 0, $len));

We use it in a template like this:

<p>{$text|shortify}</p>
<p>{$text|shortify:100}</p>

Filters

batch (int $length, mixed $item): array

Filter that simplifies the listing of linear data in the form of a table. It returns an array of array with the given number of items. If you provide a second parameter this is used to fill up missing items on the last row.

{var $items = ['a', 'b', 'c', 'd', 'e']}
<table>
{foreach ($items|batch: 3, 'No item') as $row}
	<tr>
		{foreach $row as $column}
			<td>{$column}</td>
		{/foreach}
	</tr>
{/foreach}
</table>

Prints:

<table>
	<tr>
		<td>a</td>
		<td>b</td>
		<td>c</td>
	</tr>
	<tr>
		<td>d</td>
		<td>e</td>
		<td>No item</td>
	</tr>
</table>

See also group and iterateWhile tag.

breakLines

Inserts HTML line breaks before all newlines.

{var $s = "Text & with \n newline"}
{$s|breakLines}    {* outputs "Text &amp; with <br>\n newline" *}

bytes (int $precision=2)

Formats the size in bytes into a human-readable form. If the locale is set, the corresponding decimal and thousand separators are used.

{$size|bytes}     0 B, 1.25 GB, …
{$size|bytes:0}   10 B, 1 GB, …

ceil (int $precision=0)

Rounds a number up to a given precision.

{=3.4|ceil}         {* outputs 4      *}
{=135.22|ceil:1}    {* outputs 135.3  *}
{=135.22|ceil:3}    {* outputs 135.22 *}

See also floor, round.

capitalize

Returns a title-cased version of the value. Words will start with uppercase letters, all remaining characters are lowercase. Requires PHP extension mbstring.

{='i like LATTE'|capitalize}  {* outputs 'I Like Latte' *}

See also firstUpper, lower, upper.

checkUrl

Enforces URL sanitization. It checks if the variable contains a web URL (ie. HTTP/HTTPS protocol) and prevents the writing of links that may pose a security risk.

{var $link = 'javascript:window.close()'}
<a data-href={$link|checkUrl}>checked</a>
<a data-href={$link}>unchecked</a>

Prints:

<a data-href="">checked</a>
<a data-href="javascript:window.close()">unchecked</a>

See also nocheck.

clamp (int|float $min, int|float $max)

Returns value clamped to the inclusive range of min and max.

{$level|clamp: 0, 255}

Also exists as function.

dataStream (string $mimetype=detect)

Converts the content to data URI scheme. It can be used to insert images into HTML or CSS without the need to link external files.

Lets have an image in a variable $img = Image::fromFile('obrazek.gif'), then

<img src={$img|dataStream}>

Prints for example:

<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUA
AAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO
9TXL0Y4OHwAAAABJRU5ErkJggg==">

Requires PHP extension fileinfo.

date (string $format)

Formats the date and time according to the mask used by the PHP function date. The filter accepts the date in UNIX timestamp format, as a string, or as a DateTimeInterface object.

{$today|date:'j. n. Y'}

See also localDate.

escapeUrl

Escapes a variable to be used as a parameter in URL.

<a href="http://example.com/{$name|escapeUrl}">{$name}</a>

See also query.

explode (string $separator='')

Splits a string by the given delimiter and returns an array of strings. Alias for split.

{='one,two,three'|explode:','}    {* returns ['one', 'two', 'three'] *}

If the delimiter is an empty string (default value), the input will be divided into individual characters:

{='123'|explode}                  {* returns ['1', '2', '3'] *}

You can use also alias split:

{='1,2,3'|split:','}              {* returns ['1', '2', '3'] *}

See also implode.

first

Returns the first element of array or character of string:

{=[1, 2, 3, 4]|first}    {* outputs 1 *}
{='abcd'|first}          {* outputs 'a' *}

See also last, random.

floor (int $precision=0)

Rounds a number down to a given precision.

{=3.5|floor}        {* outputs 3      *}
{=135.79|floor:1}   {* outputs 135.7  *}
{=135.79|floor:3}   {* outputs 135.79 *}

See also ceil, round.

firstUpper

Converts a first letter of value to uppercase. Requires PHP extension mbstring.

{='the latte'|firstUpper}  {* outputs 'The latte' *}

See also capitalize, lower, upper.

group (string|int|\Closure $by): array

The filter groups the data according to different criteria.

In this example, the rows in the table are grouped by the column categoryId. The output is an array of arrays where the key is the value in the column categoryId. Read the detailed instructions.

{foreach ($items|group: categoryId) as $categoryId => $categoryItems}
    <ul>
        {foreach $categoryItems as $item}
            <li>{$item->name}</li>
        {/foreach}
    </ul>
{/foreach}

See also batch, the group function, and the iterateWhile tag.

implode (string $glue='')

Return a string which is the concatenation of the strings in the array. Alias for join.

{=[1, 2, 3]|implode}      {* outputs '123' *}
{=[1, 2, 3]|implode:'|'}  {* outputs '1|2|3' *}

You can also use an alias join:

{=[1, 2, 3]|join}         {* outputs '123' *}

indent (int $level=1, string $char="\t")

Indents a text from left by a given number of tabs or other characters which we specify in the second optional argument. Blank lines are not indented.

<div>
{block |indent}
<p>Hello</p>
{/block}
</div>

Prints:

<div>
	<p>Hello</p>
</div>

last

Returns the last element of array or character of string:

{=[1, 2, 3, 4]|last}    {* outputs 4 *}
{='abcd'|last}          {* outputs 'd' *}

See also first, random.

length

Returns length of a string or array.

• for strings, it will return length in UTF‑8 characters
• for arrays, it will return count of items
• for objects that implement the Countable interface, it will use the return value of the count()
• for objects that implement the IteratorAggregate interface, it will use the return value of the iterator_count()

{if ($users|length) > 10}
	...
{/if}

localDate (?string $format=null, ?string $date=null, ?string $time=null)

Formats date and time according to the locale, ensuring consistent and localized display of time data across different languages and regions. The filter accepts the date as a UNIX timestamp, string, or DateTimeInterface object.

{$date|localDate}                  {* 15. dubna 2024 *}
{$date|format: yM}                 {* 4/2024 *}
{$date|localDate: date: medium}    {* 15. 4. 2024 *}

If you use the filter without any parameters, it will output the date in the long format level, as explained further.

a) Using the format

The format parameter describes which time components should be displayed. It uses letter codes, where the number of repetitions affects the width of the output:

The order of the codes in the format doesn’t matter, as the order of components will be displayed according to the locale's conventions. Therefore, the format is locale-independent. For example, the format yyyyMMMMd in the en_US locale outputs April 15, 2024, while in the cs_CZ locale it outputs 15. dubna 2024:

b) Using preset styles

The date and time parameters determine the level of detail for the date and time display. You can choose from several levels: full, long, medium, short. You can display just the date, just the time, or both:

For the date, you can also use the prefix relative- (e.g., relative-short), which for dates close to the present will display yesterday, today, or tomorrow; otherwise, it will display in the standard way.

{$date|localDate: date: relative-short}    {* yesterday *}

See also date.

lower

Converts a value to lowercase. Requires PHP extension mbstring.

{='LATTE'|lower}   {* outputs 'latte' *}

See also capitalize, firstUpper, upper.

nocheck

Prevents automatic URL sanitization. Latte automatically checks if the variable contains a web URL (ie. HTTP/HTTPS protocol) and prevents the writing of links that may pose a security risk.

If the link uses a different scheme, such as javascript: or data:, and you are sure of its contents, you can disable the check via |nocheck.

{var $link = 'javascript:window.close()'}

<a href={$link}>checked</a>
<a href={$link|nocheck}>unchecked</a>

Prints:

<a href="">checked</a>
<a href="javascript:window.close()">unchecked</a>

See also checkUrl.

noescape

Disables automatic escaping.

{var $trustedHtmlString = '<b>hello</b>'}
Escaped: {$trustedHtmlString}
Unescaped: {$trustedHtmlString|noescape}

Prints:

Escaped: <b>hello</b>
Unescaped: <b>hello</b>

Misuse of the noescape filter can lead to an XSS vulnerability! Never use it unless you are absolutely sure what you are doing and that the string you are printing comes from a trusted source.

number (int $decimals=0, string $decPoint='.', string $thousandsSep=',')

Formats a number to a specified number of decimal places. If the locale is set, the corresponding decimal and thousand separators are used.

{1234.20|number}              1,234
{1234.20|number:1}            1,234.2
{1234.20|number:2}            1,234.20
{1234.20|number:2, ',', ' '}  1 234,20

number (string $format)

The format parameter allows you to define the appearance of numbers exactly according to your needs. It requires a set locale. The format consists of several special characters, the complete description of which can be found in the DecimalFormat documentation:

• 0 mandatory digit, always displayed even if it's zero
• # optional digit, displayed only if the number has a digit in that place
• @ significant digit, helps to display the number with a certain number of significant digits
• . marks where the decimal separator should be (comma or dot, depending on the locale)
• , used to separate groups of digits, usually thousands
• % multiplies the number by 100 and adds the percent sign

Let's look at some examples. In the first example, two decimal places are mandatory; in the second, they are optional. The third example shows padding with zeros on both sides, and the fourth displays only the existing digits:

{1234.5|number: '#,##0.00'}     {* 1,234.50 *}
{1234.5|number: '#,##0.##'}     {* 1,234.5 *}
{1.23  |number: '000.000'}      {* 001.230 *}
{1.2   |number: '##.##'}        {* 1.2 *}

Significant digits determine how many digits, regardless of the decimal point, should be displayed, rounding the number if necessary:

{1234|number: '@@'}             {* 1200 *}
{1234|number: '@@@'}            {* 1230 *}
{1234|number: '@@@#'}           {* 1234 *}
{1.2345|number: '@@@'}          {* 1.23 *}
{0.00123|number: '@@'}          {* 0.0012 *}

An easy way to display a number as a percentage. The number is multiplied by 100 and the % sign is added:

{0.1234|number: '#.##%'}        {* 12.34% *}

We can define a different format for positive and negative numbers, separated by a ; character. This way, for example, positive numbers can be displayed with a + sign:

{42|number: '#.##;(#.##)'}      {* 42 *}
{-42|number: '#.##;(#.##)'}     {* (42) *}
{42|number: '+#.##;-#.##'}      {* +42 *}
{-42|number: '+#.##;-#.##'}     {* -42 *}

Remember that the actual appearance of numbers may vary depending on the locale settings. For example, in some countries, a comma is used instead of a dot as a decimal separator. This filter automatically accounts for this, so you don't need to worry about it.

padLeft (int $length, string $pad=' ')

Pads a string to a certain length with another string from left.

{='hello'|padLeft: 10, '123'}  {* outputs '12312hello' *}

padRight (int $length, string $pad=' ')

Pads a string to a certain length with another string from right.

{='hello'|padRight: 10, '123'}  {* outputs 'hello12312' *}

query

Dynamically generates a query string in the URL:

<a href="http://example.com/?{[name: 'John Doe', age: 43]|query}">click</a>
<a href="http://example.com/?search={$search|query}">search</a>

Prints:

<a href="http://example.com/?name=John+Doe&amp;age=43">click</a>
<a href="http://example.com/?search=Foo+Bar">search</a>

Keys with a value of null are omitted.

See also escapeUrl.

random

Returns random element of array or character of string:

{=[1, 2, 3, 4]|random}    {* example output: 3 *}
{='abcd'|random}          {* example output: 'b' *}

See also first, last.

repeat (int $count)

Repeats the string x-times.

{='hello'|repeat: 3}  {* outputs 'hellohellohello' *}

replace (string|array $search, string $replace='')

Replaces all occurrences of the search string with the replacement string.

{='hello world'|replace: 'world', 'friend'}  {* outputs 'hello friend' *}

Multiple replacements can be made at once:

{='hello world'|replace: [h => l, l => h]}  {* outputs 'lehho worhd' *}

replaceRE (string $pattern, string $replace='')

Replaces all occurrences according to regular expression.

{='hello world'|replaceRE: '/l.*/', 'l'}  {* outputs 'hel' *}

reverse

Reverses given string or array.

{var $s = 'Nette'}
{$s|reverse}    {* outputs 'etteN' *}
{var $a = ['N', 'e', 't', 't', 'e']}
{$a|reverse}    {* returns ['e', 't', 't', 'e', 'N'] *}

round (int $precision=0)

Rounds a number to a given precision.

{=3.4|round}        {* outputs 3      *}
{=3.5|round}        {* outputs 4      *}
{=135.79|round:1}   {* outputs 135.8  *}
{=135.79|round:3}   {* outputs 135.79 *}

See also ceil, floor.

slice (int $start, ?int $length=null, bool $preserveKeys=false)

Extracts a slice of an array or a string.

{='hello'|slice: 1, 2}           {* outputs 'el' *}
{=['a', 'b', 'c']|slice: 1, 2}   {* outputs ['b', 'c'] *}

The slice filter works as the array_slice PHP function for arrays and mb_substr for strings with a fallback to iconv_substr in UTF‑8 mode.

If the start is non-negative, the sequence will start at that start in the variable. If start is negative, the sequence will start that far from the end of the variable.

If length is given and is positive, then the sequence will have up to that many elements in it. If the variable is shorter than the length, then only the available variable elements will be present. If length is given and is negative then the sequence will stop that many elements from the end of the variable. If it is omitted, then the sequence will have everything from offset up until the end of the variable.

Filter will reorder and reset the integer array keys by default. This behaviour can be changed by setting preserveKeys to true. String keys are always preserved, regardless of this parameter.

sort (?Closure $comparison, string|int|\Closure|null $by=null, string|int|\Closure|bool $byKey=false)

The filter sorts elements of an array or iterator while preserving their associative keys. When a locale is set, the sorting follows its rules unless a custom comparison function is specified.

{foreach ($names|sort) as $name}
	...
{/foreach}

Array sorted in reverse order.

{foreach ($names|sort|reverse) as $name}
	...
{/foreach}

You can specify a custom comparison function for sorting (the example shows how to reverse the sort from largest to smallest):

{var $reverted = ($names|sort: fn($a, $b) => $b <=> $a)}

The |sort filter also allows you to sort elements by key:

{foreach ($names|sort: byKey: true) as $name}
	...
{/foreach}

If you need to sort a table by a specific column, you can use the by parameter. The value 'name' in the example specifies that sorting will be done by $row->name or $row['name'], depending on whether $row is an array or an object:

{foreach ($items|sort: by: 'name') as $item}
	{$item->name}
{/foreach}

You can also define a callback function that determines the value to sort by:

{foreach ($items|sort: by: fn($items) => $items->category->name) as $item}
	{$item->name}
{/foreach}

The byKey parameter can be used in the same way.

spaceless

Removes unnecessary whitespace from the output. You can also use alias strip.

{block |spaceless}
	<ul>
		<li>Hello</li>
	</ul>
{/block}

Prints:

<ul> <li>Hello</li> </ul>

stripHtml

Converts HTML to plain text. That is, it removes HTML tags and converts HTML entities to text.

{='<p>one &lt; two</p>'|stripHtml}  {* outputs 'one < two' *}

The resulting plain text can naturally contain characters that represent HTML tags, for example '<p>'|stripHtml is converted to <p>. Never output the resulting text with |noescape, as this may lead to a security vulnerability.

substr (int $offset, ?int $length=null)

Extracts a slice of a string. This filter has been replaced by a slice filter.

{$string|substr: 1, 2}

translate (…$args)

It translates expressions into other languages. To make the filter available, you need set up translator. You can also use the tags for translation.

<a href="basket">{='Baskter'|translate}</a>
<span>{$item|translate}</span>

trim (string $charlist=" \t\n\r\0\x0B\u{A0}")

Strip leading and trailing characters, by default whitespace.

{='  I like Latte.  '|trim}    {* outputs 'I like Latte.' *}
{='  I like Latte.'|trim: '.'} {* outputs '  I like Latte' *}

truncate (int $length, string $append='…')

Shortens a string to the maximum given length but tries to preserve whole words. If the string is truncated it adds ellipsis at the end (this can be changed by the second parameter).

{var $title = 'Hello, how are you?'}
{$title|truncate:5}  {* Hell…                *}
{$title|truncate:17} {* Hello, how are…      *}
{$title|truncate:30} {* Hello, how are you?  *}

upper

Converts a value to uppercase. Requires PHP extension mbstring.

{='latte'|upper}  {* outputs 'LATTE' *}

See also capitalize, firstUpper, lower.

webalize

Converts to ASCII.

Converts spaces to hyphens. Removes characters that aren’t alphanumerics, underscores, or hyphens. Converts to lowercase. Also strips leading and trailing whitespace.

{var $s = 'Our 10. product'}
{$s|webalize}    {* outputs 'our-10-product' *}

Requires package nette/utils.