Multiply two variables

[mabroens]

Body of the issue

Hi team,
in my PO i would like to multiply 2 variables but that fails.

{% load i18n %}
{% load report %}
{% load barcode %}
{% load inventree_extras %}
{% load markdownify %}

{% for line in lines.all %}
          {% with Qty=line.quantity PackQty=line.part.pack_quantity|default:1 Packaging=line.part.packaging%}
          {% multiply Qty 1 as TotalQty %}
  
          <tr>
              <td>
  				<div class='thumb-container'>
                      <img src='{% part_image line.part.part %}' class='part-thumb'>
                  </div>
              </td>
              <td>
                  <div class='part-text'>
  					{% if line.part.part.revision %} 
  					  <strong>{{ line.part.part.IPN }} {{line.part.part.revision}}-Sample</strong>
  					{% else %} 
                        <strong>{{ line.part.part.name }}</strong>
  					{% endif %}
  					<br><br>
  					{{ line.part.part.description }}
                  </div>
              </td>
              
            <td>{% decimal Qty %}</td>
            <td>{{ Packaging }}</td> 
            <td>{% decimal PackQty %}</td>
            <td>{% decimal TotalQty %}</td>
  			<td>{% render_currency line.price decimal_places=2 currency=order.customer.currency include_symbol=False%}</td>
  			<td>{% render_currency line.total_line_price decimal_places=2 currency=order.customer.currency include_symbol=False%}</td>
          </tr>
          {% endwith %}
        {% endfor %}

in teh above i have: {% multiply Qty 1 as TotalQty %} which works but {% multiply Qty PackQty as TotalQty %} Fails mostlikly becaus these variables are strings and not numbers.

how can i get to what i aim for??

the idea is that it pirnt 3 Tape 1000 3000.
so at the moment only the multiply is missing and failing

pleae advice

[SchrodingersGat]

The multiply tag expects numbers, that will need to be updated to convert the inputs to numbers first:

InvenTree/src/backend/InvenTree/report/templatetags/report.py

Line 408 in bc382cd

def multiply(x, y):

The other maths functions should also he updated accordingly.

Perhaps you want to submit a PR to fix this?

[mabroens]

I would assume it could be as simple as:@register.simple_tag()

def multiply(x, y):
    """Multiply two values together, converting to float if needed."""
    try:
        return float(x) * float(y)
    except (TypeError, ValueError):
        return 0.0

can i just try this locally? i mean if i edit inventree/InvenTree/report/templatetags/report.py and change it like that it does not seem to work when i run my template. or am i missing something?

[SchrodingersGat]

I think that your code in the template is not correct also. Please refer to this example

I think it should be {% multiply x y as result %}

[mabroens]

well i think that is what i have.

when i do
{% multiply Qty 1 as TotalQty %} that works this prints 3
and
{% multiply 1 PackQty as TotalQty %} works this prints 1000

but {% multiply PackQty Qty as TotalQty %} does not work, but should print 3000

[SchrodingersGat]

This works for me on latest code:

<td>{% multiply line.quantity line.purchase_price.amount as result %}Result: {{ result }}</td>

What version are you running?

[mabroens]

agree that works for me as well and
<td>{% multiply Qty line.purchase_price.amount as result %}Result: {{ result }}</td>
also works for me

but
<td>{% multiply line.quantity line.part.pack_quantity as result %}Result: {{ result }}</td>

does not work

[SchrodingersGat]

Possible that "pack_quantity" is not a proper number in this context?

[mabroens]

I hear you but than why would these work:
when i do
{% multiply Qty 1 as TotalQty %} that works this prints 3
and
{% multiply 1 PackQty as TotalQty %} works this prints 1000

so in my undrstanding multiply of either works but together fails.
both are strings if i understood correct. so typically multiply should fail in all caese but it does not.

That mentioned if i change the python code like mentioned above. should that work? i tried it by adding a new function but calling that new function already fails seems like the new function is not found when running the django. i have tried restarting Inventree baut that also had the same effect.

even made a new function:

@register.simple_tag()
def my_multiply(x, y):
    """Multiply two numbers together."""
    return 9999

and

def multiply_mb(x, y):
    """Multiply two values together, converting to float if needed."""
    try:
        return float(x) * float(y)
    except (TypeError, ValueError):
        return 0.0

but calling both results in an error. am i missing something?

[SchrodingersGat]

Not sure what is going on, here's my latest attempt in "master":

            <td>
              Quantity: {{ line.quantity }}<br>
              Pack Qty: {{ line.part.pack_quantity_native }}<br>
              {% multiply line.quantity line.part.pack_quantity_native as result %}
              Result: {{ result }}
            </td>

[mabroens]

indeed that works.
but you are using line.part.pack_quantity_native and i was using line.part.pack_quantity

but you solved the mistery :-)

thank you.