How to set a value of a variable inside a template code?

user_99662 0
Viewed 407043

Say I have a template

<html>
<div>Hello {{name}}!</div>
</html>

While testing it, it would be useful to define the value of the variable without touching the python code that invokes this template. So I'm looking for something like this

{% set name="World" %}     
<html>
<div>Hello {{name}}!</div>
</html>

Does something like this exists in Django?

django-templates django
9 Answers

You can use the with template tag.

{% with name="World" %}     
<html>
<div>Hello {{name}}!</div>
</html>
{% endwith %}
user_522070

An alternative way that doesn't require that you put everything in the "with" block is to create a custom tag that adds a new variable to the context. As in:

class SetVarNode(template.Node):
    def __init__(self, new_val, var_name):
        self.new_val = new_val
        self.var_name = var_name
    def render(self, context):
        context[self.var_name] = self.new_val
        return ''

import re
@register.tag
def setvar(parser,token):
    # This version uses a regular expression to parse tag contents.
    try:
        # Splitting by None == splitting by spaces.
        tag_name, arg = token.contents.split(None, 1)
    except ValueError:
        raise template.TemplateSyntaxError, "%r tag requires arguments" % token.contents.split()[0]
    m = re.search(r'(.*?) as (\w+)', arg)
    if not m:
        raise template.TemplateSyntaxError, "%r tag had invalid arguments" % tag_name
    new_val, var_name = m.groups()
    if not (new_val[0] == new_val[-1] and new_val[0] in ('"', "'")):
        raise template.TemplateSyntaxError, "%r tag's argument should be in quotes" % tag_name
    return SetVarNode(new_val[1:-1], var_name)

This will allow you to write something like this in your template:

{% setvar "a string" as new_template_var %}

Note that most of this was taken from here

user_24940

There are tricks like the one described by John; however, Django's template language by design does not support setting a variable (see the "Philosophy" box in Django documentation for templates).
Because of this, the recommended way to change any variable is via touching the Python code.

Roberto_Liffredo_439270
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