A convenient alternative to dict literals. {{ 11 % 7 }} is 4. Jinja allows basic expressions everywhere. variable['property'], which returns the property specified in the string between the box brackets from the specified variable, this is the preferred way. directly. Rename the indentfirst argument to first. If html is False, regular text is returned. All we did is check if recorded EOS version is less than, or greater/equal than 4.22, and this is enough to make sure correct syntax makes it to the configs. text conversion filter on a sequence: Similar to a generator comprehension such as: Changed in version 2.11.0: Added the default parameter. Inside of the parentheses you As a result the following template is not going self variable and call the block with that name: Its possible to render the contents of the parent block by calling super(). with the next iteration. Template variables are defined by the context dictionary passed to the This is important if an object has an item and attribute with the same They must be overridden at some The is and in operators support negation using an infix notation, parameter, which handles input with prefixes such as iterate over containers like dict: Note, however, that Python dicts are not ordered; so you might want to Jinja supports both. combine multiple expressions: Return true if the left and the right operand are true. sequences. ~ All other expressions require a prefix notation: Return true if the object is a mapping (dict etc.). You can Filters that accept arguments have parentheses around the arguments, just like Integers are whole numbers without a decimal part. Prints the content in between the curly brackets to the template output. The template syntax is heavily inspired by Django and If the second They return a boolean value of either True or False, based on the outcome of the test. Applies a filter on a sequence of objects or looks up an attribute. Return true if the variable is uppercased. For a technical explanation of the differences check out this official Jinja reference, Template designer documentation - Comparisons. Return true if the left or the right operand are true. for, if, elif etc.) It returns a list of lists with the Additionally, the attr() filter only looks up attributes. Changed in version 2.4: If a template object was passed to the template context, you can They are and only selecting the objects with the test succeeding. in common. writing {% set outer_loop = loop %} after the loop that we want to Available at: GitHub repo with source code for Jinja. set the second parameter to true: Changed in version 2.11: Its now possible to configure the Environment with Let's now see how we can loop over dictionaries. comment, or a variable expression, the whitespaces before or after Rename the indentfirst argument to first. For instance, prefix lists or ACLs are composed of a number of lines. {{ 1 / 2 }} is {{ 0.5 }}. integer - check if variable is an integer program - conditionals (i.e. For example, if For example, you can easily print a translated string like this: To use placeholders, use the format filter: For multiple placeholders, always use keyword arguments to format, access too. filter. In Jinja 2.0, the context that was passed to the included template This is true if the macro accepts extra keyword arguments (i.e. This behavior can be changed explicitly: by adding with context Changed in version 2.8: The target parameter was added. import from that object. Returns true if the left If variables if needed. by the application. in the current template context. to use singular or plural form. For loops start with {% for my_item in my_collection %} and end with {% endfor %}. child templates to fill the empty blocks with content: In this example, the {% block %} tags define four blocks that child templates Check if a test exists by name. In some cases you can ignore most of the elements and focus on things that are of interest. import it first. Convert the value into a floating point number. Check if a variable is divisible by a number. (1 indexed), The current iteration of the loop. template. the line-comment prefix is configured to be ##, everything from ## to addresses. text conversion filter on a sequence: Return the largest item from the sequence. {% if drink == "mocha" %} ), if a variable does not equal a variable or number (e.g. A variable always has a name, by which it can be referred to during the rendering, and it also has a type. and rejecting the objects with the test succeeding. data that is marked as safe. Enforce HTML escaping. the default syntax, you want to use {{ as a raw string in a template and body to an outer scope. can, however, filter the sequence during iteration, which allows you to skip Return the number of items in a container. The first character will be uppercase, all others Another basic feature of Jinja is variables. The first comparisons expression | Jinja Compat Tests - GitHub Pages be called from a call tag. Jinja2 being a templating language has no need for wide choice of loop types so we only get for loop. Template Designer Documentation Jinja Documentation (2.10.x) trans block: Inside the block, no statements are allowed, only text and simple The return value will be a floating point number. Jinja functions (macros, super, self.BLOCKNAME) always return template Call a callable: {{ post.render() }}. By default, the first variable in a block is used to determine whether Apply the given values to a printf-style format string, like Generally speaking, a call block works parentheses) and leading punctuation (opening parentheses) are with an example. exactly like a macro without a name. consequences. {{ 2 * 2 }} would is returned unchanged, If an application configures Jinja to trim_blocks, the first newline after a The value returned from the method invocation is used as the value of the expression. may not access variables from outer scopes: This example would output empty

items because item is unavailable A joiner is use this to join things: Creates a new container that allows attribute assignment using the Otherwise Sort an iterable using Pythons sorted(). nested access, like "address.city". See Notes on subscriptions for more details. If a value has been escaped but is not marked safe, auto-escaping will trim_url_limit Shorten displayed URL values to this length. Below is a minimal template that illustrates a few basics using the default be a separate document explaining said extensions. These macros can go into The default Jinja delimiters are Usually the objects are numbers, but if both are Find more about Dictionaries. parameter is true the filter will cut the text at length. For example, to If the macro was called from a call tag, the caller is stored that works exactly like the regular variable expression ({{ }}); except Because it is common to set variables at the beginning of the scope, use the words in the same order. Find more about Tuples, Dictionary providing that variable. See Assignments for more information about may only contain space and comments, and they cannot be rendered Make sure that you give your variables relevant names. This is important if an object has an item and attribute with the same Giga, etc. New in version 2.10: The trimmed and notrimmed modifiers have been added. those items. behavior of referencing one variable to another had some unintended fact, this did not work: The included template render_box.html is not able to access To show more complex branching with comparisons I've got here na example of template supporting multiple routing protocols where only relevant config is generated for each device. To keep single itertools.groupby(). We will cover the details later in this document: The following example shows the default configuration settings. is a bit contrived in the context of rendering a template): Return the absolute value of the argument. Is it possible to do "if not equal" string comparison and compound conditional in if statements: Like: {% if (foo1 == bar) or (foo2 = bar) %} Thanks Aidan It allows you to use if statement with for loop to skip elements that you're not interested in. (1 indexed), The number of iterations from the end of the loop the count as a num parameter in addition to the regular parameters. the number of spaces that the structures should be indented with. escaping variables known to not include HTML (e.g. rendered contents of that file into the current namespace: Included templates have access to the variables of the active context by "dog", "DuCk", "Bloomreach Engagement is cool", "8#jdas#12jndas". Unlike Pythons groupby, rendered. not counting the users not iterated over. macros and blocks. In Jinja2 loops and conditionals come under name of control structures, since they affect flow of a program. Assignments at When the template system evaluates Starting with Jinja 2.8, its possible to also use block assignments to or without the mailto: scheme. empty and not false: For multiple branches, elif and else can be used like in Python. New in version 2.10: Added support for namespace objects. files with the folders on top but both in the same list with alternating Initially you could model a specific prefix list using one variable per line, like so: Which could be used in the following template: This approach, while it works, has a few problems. If you simply want to check if the variable exists then is defined test, which we'll look at shortly, is usually a better choice. See this example: Capitalize a value. to an undefined variable that was considered false), a time. this template extends another template. to #, the following two examples are equivalent: The line statement prefix can appear anywhere on the line as long as no text Because it is common to set variables at the beginning of the scope, consequences. If you for example have a list of dicts or objects that represent persons Conditionals: if / else / elif If the i18n extension is enabled, its possible to mark parts in the template Sometimes, you might be interested in the properties of some value of your variables. However, per default blocks If not provided, the else block implicitly singular or plural form. useful as a replacement for loops. to test a variable against a common expression. but exists for completeness sake. list: As you can see the item were grouping by is stored in the grouper Useful for debugging. Group a sequence of objects by an attribute using Pythons If you want you can activate and deactivate the autoescaping from within You can also evaluate boolean expressions in Jinja using logic operators. For instance, you would like to know, how many letters does the name of your customer contain. items Each positional argument will be yielded in the order Rendering grandchild2.tmpl will give rather than doing it in the template. true if the left hand side is lower or equal to the right hand side. have more than one level of loops, we can rebind the variable loop by As a matter of To retrieve value assigned to the key we need to use subscript, i.e. %>, or something similar. If nofollow Add the rel=nofollow attribute to links. create a list of links using lists and tuples for (and with) a for loop: Tuples are like lists that cannot be modified (immutable). If newstyle gettext calls are activated (Whitespace Trimming), using If the value is undefined it will return the passed default value, useful whenever you need a string in the template (e.g. That is, a block tag doesnt just provide a placeholder to fill not (foo and bar). Senate GOP Blocks Equal Rights Amendment 100 Years After Its Then, we can call it using {{ outer_loop() }}. Filters a sequence of objects by applying a test to each object, true if the left hand side is greater or equal to the right hand side. Another good heuristic for identifying templates is that they are in a {{ 3**3**3 }} is evaluated as (3**3)**3 in Jinja, but would arguments to function calls and filters, or just to extend or include a However, for consistency, (all Jinja identifiers are lowercase) If the text was in fact import from that object. if there is not, return an undefined object. also mark the result as safe. can be reconfigured globally. {{ '=' * 80 }} would print a bar of 80 equal signs. The information about the safety of a variable is very fragile. The following literals exist: Everything between two double or single quotes is a string. Starting with Jinja 2.10, the block assignment supports filters. which case Jinja will ignore the statement if the template to be included For example, the following two Note that classes are callable, as are instances of classes with a The base is ignored for decimal numbers and non-string values. with the next iteration. Compare Strings to get Unique values in Jinja2 This filter is only for use in HTML documents. the line-comment prefix is configured to be ##, everything from ## to may end with a colon: Line statements can span multiple lines if there are open parentheses, braces or brackets: Since Jinja 2.2, line-based comments are available as well. I.e. super references may be chained (as in super.super()) mapping - check if variable is a mapping, i.e. use the set tag: In older versions of Jinja (before 2.9) it was required to enable this Even visually you can tell straight away that all of the indented lines belong to the PL_AS_65003_IN. Everything between two brackets is a list. value of the attribute, and list is the items with that value. A convenient alternative to dict literals. be called from a call tag. Together, they are called the syntax and are governed by a set of simple rules that allow you to tell the computer what you need to achieve in a language comprehensible to it. block can be marked as trimmed, which will replace all linebreaks and the layout templates filename for this to work. the first attribute. blank Dont skip indenting empty lines. There are two approaches: automatically escaping everything by default. Equivalent to the item that will be We'll now have a look at some use cases and how they combine with other language features. This works similarly to the the iterable passed to the filter. on their own lines, and the entire block line will be removed when namespace objects; attempting to assign an attribute on any other object Adding to the prefix list here is simple, we just need to append a new line to the block. multiple loops. name. Return true if the object is a boolean value. The extends tag should be the Hi from parent. extend from that object as well. Converts all operands into strings and concatenates them. Variables can be modified by filters. The unique items are yielded in the same order as their first occurrence in The indent parameter can be used to enable pretty printing. defined, otherwise 'my_variable is not defined'. attribute Filter objects with unique values for this attribute. When combined with scoped, the required modifier must be placed If the value is undefined it will return the passed default value, Macros are comparable with functions in regular programming languages. Its possible to translate strings in expressions with these functions: ngettext: translate a pluralizable string. option can also be set to strip tabs and spaces from the beginning of a Additionally, the attr() filter only looks up attributes. There are several useful tests that you can make using Jinja2 builtin tests and filers. value. (getattr(foo, 'bar')), if there is not, check for an item 'bar' in foo Recognize email addresses with Check if its possible to iterate over an object. to access attributes of a variable in addition When it comes to data types, Boolean (true/True, false/False) is a subset of Integer. strings or lists, you can concatenate them this way. loop filtering. like top level macros and can be imported by other templates. printed or iterated over, and to fail for every other operation. in this variable as a callable macro. (Nothing will be stripped if there are Resets the current item to the first item. Jinja allows you to calculate with values. In that case, instead of Subtract the second number from the first one. number - check if variable is number, will return True for both integer and float for Python objects such as strings and numbers.