ลูปและเงื่อนไขของ Jinja2

Sometimes you must repeat rows or hide a section. Jinja2 adds logic tags so your template can loop and branch over data.

Logic uses {% %}, not double braces. Braces output a value, while percent tags run control flow like loops and conditions.

Repeat markup with a for loop. Each pass binds the current item so you can print it inside the loop body.

Every block opens and closes. A for loop ends with endfor, which tells Jinja2 exactly where the repeated section stops.

Inside a loop, Jinja2 gives you a special loop object. Use loop.index for a 1-based counter on each pass.

A for block can include an else branch. It runs only when the list is empty, perfect for a no items message.

Show markup only when a test passes using if. It ends with endif and accepts ordinary Python-style comparisons.

Pair an if with else to handle the other case. One branch renders when true, the other when the test is false.

Chain extra cases with elif. Jinja2 checks each in order and renders the first branch whose test is true.

Nest an if inside a loop to filter as you go. This lets each item decide whether it appears in the output.

Light logic in templates is fine, but deep nesting hurts. Prepare filtered data in your view to keep markup clean.

Which delimiter does Jinja2 use for control flow like loops and conditionals?

You can now loop with for, branch with if and elif, use the loop counter, and handle empty lists, all inside templates. Well done! ✨