How to use For loop in Jinja2.

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by dot icon Updated: Nov 28, 2023

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Jinja2 is a powerful and widely used template engine for Python. It is often employed in web development frameworks such as Flask and Django to generate.   

The for-loop module in Jinja2 allows you to iterate over a sequence. It can be as a list or dictionary and generate content based on each item in the sequence.   


Types of Loops in Jinja 2: Jinja2 supports various types of loops, ranging from simple loops to more loops.   

  • Simple for loop   
  • Loop Variables   
  • Looping through a Range   
  • Nested Loops   
  • Looping through Dictionaries   
  • Looping through Lists   
  • Looping with Conditions   


Key Points of For loop in Jinja 2:   

  1. Syntax: The basic syntax of a Jinja2 for loop: {% for item in sequence %} ... {% end for %}. The items are variables representing each element in the sequence.   
  2. Loop Variables: Jinja2 provides loop variables like loop.index, loop. Index(), loop.first. These variables offer information about the current iteration index.   
  3. Iterating Over a Range: The use of the range function to iterate a specific number of times.   
  4. Nested Loops: Jinja2 supports nested loops for iterating over multiple sequences simultaneously. It is useful for handling hierarchical data structures.   
  5. Looping through Dictionaries: The Iterating over dictionaries using the items () method to access.   
  6. Looping with Conditions: It Combines loops with conditional statements using the if clause. It Allows selective iteration based on certain conditions.   
  7. Looping with Filters: Applying filters within a loop to change the variable output.   
  8. Limit and Offset: Use parameters like limit and offset to control iteration number.   
  9. Best Practices: It Highlights best practices for efficient and readable template code. It Encourages the use of meaningful variable names and clear indentation for maintenance.   


In summary, the Jinja2 for loop module stands out for its simplicity and flexibility. Jinja2 provides an efficient solution for simple lists or complex nested data structures. It helps developers who work on projects requiring dynamic content generation.   

Fig: Preview of the output that you will get on running this code from your IDE.


In this solution we are using Jinja 2 library of Python.


Follow the steps carefully to get the output easily.

  1. Download and Install the Jupyter Notebook on your computer.
  2. Open the terminal and install the required libraries with the following commands.
  3. Create a new Python file on your Notebook.
  4. Copy the snippet using the 'copy' button and paste it into your Python.
  5. Remove 5 to 17 lines from the code.
  6. Run the current file to generate the output.

I hope you found this useful.

I found this code snippet by searching for ' flask - jinja template for loop increasing loop index' in Kandi. You can try any such use case!

Environment Tested

I tested this solution in the following versions. Be mindful of changes when working with other versions.

  1. Jupyter Notebook (anaconda 3) 6.0.1 Version
  2. The solution is created in Python 3.8 Version
  3. Jinja 2 3.1.2 Version.

Using this solution, we can be able to use For loop in Jinja2 using Python with simple steps. This process also facilities an easy way to use, hassle-free method to create a hands-on working version of code which would help us to use For loop in Jinja2 using Python.

Dependent Library

jinjaby pallets

Python doticonstar image 9285 doticonVersion:3.1.2doticon
License: Permissive (BSD-3-Clause)

A very fast and expressive template engine.


            jinjaby pallets

            Python doticon star image 9285 doticonVersion:3.1.2doticon License: Permissive (BSD-3-Clause)

            A very fast and expressive template engine.

                      You can search for any dependent library on kandi like 'jinja'.


                      1. What is jinja2, and how is it used as a template language in web development?   

                      Jinja2 is a popular and powerful template engine for Python. It helps in generating dynamic content in web applications but applies in content. Jinja2 is widely used in web frameworks such as Flask and Django. It is important in separating the logic of an application from its layers.   

                      • Template Syntax   
                      • Variable Substitution   
                      • Control Structures   
                      • Filters   
                      • Template Inheritance   
                      • Usage in Web Development   
                      • Setting up the Environment   
                      • Creating Templates   
                      • Rendering Templates   
                      • Passing Data   
                      • Template Inheritance and Structure   
                      • Dynamic Content   


                      2. What is the relationship between Flask and jinja2 loops?   

                      Flask and Jinja2 are closely integrated, and Jinja2 is the default template engine. The relationship between Flask and Jinja2 loops is significant. It enables dynamic content generation in Flask web applications.   

                      The close integration between Flask and Jinja2 allows developers to seamlessly incorporate content. Jinja2 loops provide a flexible way to generate dynamic content within templates. This relationship simplifies the process of building dynamic web applications in Python.   


                      3. What steps to follow when creating a loop variable in a jinja2 template?   

                      By Creating a loop variable in a Jinja2 template involves using the loop construct.   

                      • Start a for Loop   
                      • Access Loop Variables   
                      • Filtering and Conditional Statements   
                      • Nested Loops   
                      • Limiting and Offset   


                      4. How does the context of a template affect the execution of a jinja2 loop?   

                      The context of a template refers to the data and variables available to the template. The context is crucial in the execution of a Jinja2 loop influencing.   

                      • Data Passed to the Template   
                      • Looping Over Context Variables   
                      • Accessing Context Variables in the Loop   
                      • Conditional Execution Based on Context   
                      • Nested Contexts   
                      • Dynamic Context Updates   


                      5. Which template engine is best suited for developing complex applications using jinja2 loops?   

                      Jinja2 is a versatile and widely used template engine in the Python ecosystem. The choice of the best template engine depends on several factors. It includes personal preferences and the specific requirements of your project.   

                      • Jinja2   
                      • Mako   
                      • Django Templates   
                      • Chameleon   
                      • Nunavut   



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