# Filters Reference

URL: /docs/reference/filters/
Section: reference
Tags: reference, filters

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Filters Reference Complete reference for all built-in filters. String Filters abs Return absolute value. {{ -5 | abs }} → 5 capitalize Capitalize first character. {{ "hello world" | capitalize }} → Hello world center Center string in given width. {{ "hi" | center(10) }} → " hi " escape / e HTML-escape the value. {{ "<script>" | escape }} → <script> {{ "<b>" | e }} → <b> format Format string with arguments. {{ "Hello, {}!" | format(name) }} {{ "{} + {} = {}" | format(1, 2, 3) }} indent Indent text lines. {{ text | indent(4) }} {{ text | indent(4, first=true) }} lower Convert to lowercase. {{ "HELLO" | lower }} → hello replace Replace occurrences. {{ "hello" | replace("l", "L") }} → heLLo {{ "aaa" | replace("a", "b", 2) }} → bba safe Mark as safe HTML (no escaping). {{ html_content | safe }} {{ trusted | safe(reason="sanitized") }} striptags Remove HTML tags. {{ "<p>Hello</p>" | striptags }} → Hello title Title case. {{ "hello world" | title }} → Hello World trim / strip Remove whitespace. {{ " hello " | trim }} → hello {{ "xxhelloxx" | trim("x") }} → hello truncate Truncate to length. {{ text | truncate(50) }} {{ text | truncate(50, killwords=true) }} {{ text | truncate(50, end="[...]") }} upper Convert to uppercase. {{ "hello" | upper }} → HELLO urlencode URL-encode a string. {{ "hello world" | urlencode }} → hello%20world wordcount Count words. {{ "hello world" | wordcount }} → 2 wordwrap Wrap text at width. {{ long_text | wordwrap(80) }} Collection Filters batch Group items into batches. {% for row in items | batch(3) %} {% for item in row %}{{ item }}{% end %} {% end %} first Return first item. {{ items | first }} {{ [1, 2, 3] | first }} → 1 groupby Group by attribute. {% for group in posts | groupby("category") %} <h2>{{ group.grouper }}</h2> {% for post in group.list %} {{ post.title }} {% end %} {% end %} join Join with separator. {{ items | join(", ") }} {{ [1, 2, 3] | join("-") }} → 1-2-3 last Return last item. {{ items | last }} {{ [1, 2, 3] | last }} → 3 length / count Return item count. {{ items | length }} {{ "hello" | length }} → 5 list Convert to list. {{ range(5) | list }} → [0, 1, 2, 3, 4] map Extract attribute from items. {{ users | map(attribute="name") | join(", ") }} max Return maximum. {{ [1, 5, 3] | max }} → 5 {{ items | max(attribute="score") }} min Return minimum. {{ [1, 5, 3] | min }} → 1 {{ items | min(attribute="price") }} reject Reject items matching test. {{ items | reject("none") | list }} rejectattr Reject items where attribute matches. {{ posts | rejectattr("is_draft") | list }} {{ users | rejectattr("age", "lt", 18) | list }} reverse Reverse sequence. {{ [1, 2, 3] | reverse | list }} → [3, 2, 1] select Select items matching test. {{ items | select("defined") | list }} selectattr Select items where attribute matches. {{ posts | selectattr("is_published") | list }} {{ users | selectattr("role", "eq", "admin") | list }} skip Skip first N items. {{ items | skip(5) }} {{ posts | skip(10) | take(10) }} slice Slice into groups. {% for column in items | slice(3) %} <div class="column"> {% for item in column %}{{ item }}{% end %} </div> {% end %} sort Sort sequence. {{ items | sort }} {{ items | sort(reverse=true) }} {{ posts | sort(attribute="date") }} {{ pages | sort(attribute="weight,title") }} sum Sum values. {{ [1, 2, 3] | sum }} → 6 {{ items | sum(attribute="price") }} take Take first N items. {{ items | take(5) }} {{ posts | sort(attribute="date", reverse=true) | take(3) }} unique Remove duplicates. {{ items | unique }} {{ posts | unique(attribute="category") }} compact Remove None/falsy values. {{ [1, None, 2, "", 3] | compact }} → [1, 2, 3] {{ items | compact(truthy=false) }} {# Only remove None #} Number Filters float Convert to float. {{ "3.14" | float }} → 3.14 {{ "bad" | float(default=0.0) }} → 0.0 int Convert to integer. {{ "42" | int }} → 42 {{ "bad" | int(default=0) }} → 0 round Round number. {{ 3.7 | round }} → 4 {{ 3.14159 | round(2) }} → 3.14 {{ 3.5 | round(method="ceil") }} → 4 {{ 3.5 | round(method="floor") }} → 3 filesizeformat Format bytes as human-readable. {{ 1024 | filesizeformat }} → 1.0 kB {{ 1048576 | filesizeformat(binary=true) }} → 1.0 MiB format_number / commas Format with thousands separator. {{ 1234567 | format_number }} → 1,234,567 {{ 1234.5 | format_number(2) }} → 1,234.50 {{ 1000000 | commas }} → 1,000,000 Utility Filters attr Get attribute from object. {{ user | attr("name") }} default / d Return default if undefined or None. {{ missing | default("N/A") }} {{ value | d("fallback") }} {{ maybe_false | default(true, boolean=true) }} dictsort Sort dict and return pairs. {% for key, value in data | dictsort %} {{ key }}: {{ value }} {% end %} get Safe dictionary/object access. {{ config | get("timeout", 30) }} {{ data | get("items") }} {# Avoids method name conflict #} pprint Pretty-print value. <pre>{{ data | pprint }}</pre> require Require non-None value. {{ user.id | require("User ID required") }} tojson Convert to JSON. <script>const data = {{ config | tojson }};</script> {{ data | tojson(indent=2) }} xmlattr Convert dict to XML attributes. <div{{ attrs | xmlattr }}></div> Debug Filters debug Print debug info to stderr. {{ posts | debug }} {{ posts | debug("my posts") }} {{ items | debug(max_items=10) }} Randomization Filters Warning: These are impure (non-deterministic). random Return random item. {{ items | random }} shuffle Return shuffled copy. {{ items | shuffle }} See Also Filter Syntax — Using filters Custom Filters — Create filters

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