nnThe ** operator in Jinja2 raises the left operand to the power of the right operand. For example, {{ 2 ** 3 }} would return 8. This operator is used for performing exponentiation in your templates. Its behavior is generally consistent with Python’s ** operator, with one key difference in chained operations.nn

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How It Works

nThe ** operator performs exponentiation on two numerical values. When Jinja2 encounters the expression number1 ** number2, it calculates the result and returns it. This is useful for mathematical calculations, such as in financial models, scientific data, or scoring algorithms.nnImportant Note on Chained Operations: Unlike Python, which evaluates chained power expressions from right to left (e.g., `3**3**3` is `3**(3**3)`), Jinja2 evaluates them from left to right. This means `{{ 3 ** 3 ** 3 }}` is evaluated as `(3 ** 3) ** 3`. It is highly recommended to use parentheses to be explicit about the order of operations you desire, or to perform complex math in your Python code and pass the result to the template.n

Syntax

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{{ number1 ** number2 }}

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Demonstration with Code Samples

nHere are some practical examples of how to use the ** operator in a Jinja2 application.n

1. Simple Power Calculation

nThis is a straightforward use of the operator for calculating powers.nnJinja2 Templaten

{% set base = 5 %}n{% set exponent = 3 %}n<p>Result: {{ base ** exponent }}</p>

nExplanation: The template calculates `5` to the power of `3`, resulting in `125`.nn

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2. Chained Power Expression with Parentheses

nThis example demonstrates the difference in evaluation order and how to use parentheses to control it.nnJinja2 Templaten

{% set result_jinja_default = 3 ** 3 ** 2 %}n{% set result_python_style = 3 ** (3 ** 2) %}n<p>Jinja's default evaluation (left-to-right): {{ result_jinja_default }}</p>n<p>Python's style evaluation (right-to-left): {{ result_python_style }}</p>

nExplanation: The first expression `3 ** 3 ** 2` is evaluated as `(3 ** 3) ** 2`, which is `27 ** 2 = 729`. The second expression uses parentheses to force a right-to-left evaluation, `3 ** (3 ** 2)`, which is `3 ** 9 = 19683`, matching Python’s default behavior.nn