Why can't I perform a replace on a variable in template toolkit?

I am using Template Toolkit and the replace functionality isn't working. Here's my code...

开发者_开发百科  [% FOREACH item = file_conversions %]
  [% item.name | replace('a','z') %]
    <option value="[% item.name %]">[% item.name %]</option>
  [% END %]

Replace in the above case doesn't do a thing on item.name. Just for kicks, I switched it to the following...

  [% FOREACH item = file_conversions %]
  [% item.name="Janie" | replace('a','z') %]
    <option value="[% item.name %]">[% item.name %]</option>
  [% END %]

And it works perfectly.

Does anyone have an idea why I can't do a simple replace on a variable in TT?

Replace appears in two contexts in TT: as a filter, and as a virtual method for a scalar.

   Virtual method modifies the scalar:

    [% item.name.replace('a', 'z') #item.name has changed %]

   Filter modifies the output:

    [% item.name |replace('a', 'z') #item.name has not changed %]

In your original problem case, you are using a filter, therefore the value of item.name remains the same. In the "working" example, you are filtering the value "Janie" and then assigning the result to item.name:

   [% item.name = 
        'Janie' | replace('a', 'o') %]

This is an old post and you have moved on, but perhaps someone will find this helpful! (Actually, I did when I had to look a few things up to answer it!)

Hey guys! I figured it out! This works great!

  [% FOREACH item = file_conversions %]
    [% item.name = item.name.replace('a','z') %]
    <option value="[% item.name %]">[% item.name %]</option>
  [% END %]