Python Basics: How can i set two function parameters in equations?

Question

I have a basic question on python functions and parameters

Given this function:

def findArticleWithAttr(tableattrib, user_url_input):
    articles = Something.objects.filter(tableattrib=user_url_input)

I call the function with:

findArticleWithAttr(attribute1, userinput1)

tableattrib is not set by findArticleWithAttr attribute1 and just takes the latter (userinput1) parameter and replaces it.

How can i make python set both parameters in the equation?

Not sure of what are you trying here, but this Something.objects.filter(tableattrib=user_url_input) doesn't seem correct. What you're doing in there is passing user_url_input to an argument called tableattrib for the method .filter. Not sure, but I think that's not what you want... Also, what's this? Django? — Ricardo Cárdenes
– Ricardo Cárdenes, Commented Jan 4, 2012 at 23:34
@RicardoCárdenes: He's trying to allow the attribute by which to filter to be specified as an argument to findArticleWithAttr. Obviously this doesn't work, as tableattrib is treated as a keyword identifier rather than a variable identifier in this syntax. — Will Vousden
– Will Vousden, Commented Jan 4, 2012 at 23:36
Hi...yes you are right... its django...what i want is to define the parameter and attribute from an outside function...thanks for your comment — Jurudocs
– Jurudocs, Commented Jan 4, 2012 at 23:37

unutbu · Accepted Answer · 2012-01-04 23:50:34Z

8

You could use the ** double-splat operator:

def findArticleWithAttr(tableattrib, user_url_input):
    articles = Something.objects.filter(**{tableattrib : user_url_input})

Basically, the ** operator makes

func(**{'foo' : 'bar'})

equivalent to

func(foo = 'bar')

It allows you to call a function with arbitrary keyword arguments.

answered Jan 4, 2012 at 23:35

unutbu

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1 Comment

For more information about this method of passing parameters, look at "unpacking" or this relevant SO question: stackoverflow.com/questions/334655/…