Using a string as a variable name

Question

I'm collecting a lot of form parameters. Instead of writing repetitive lines like this:

def post(self):
    var1 = self.request.get('var1')
    var2 = self.request.get('var2')
    var3 = self.request.get('var3')
    var4 = self.request.get('var4')
        ...

...Is there a way to put this into a loop? Perhaps something like this:

def post(self):
    var_list = ['var1', 'var2', 'var3', 'var4', ...]
    for var in var_list:
        var = self.request.get(var)

The problem with my loop is that var is a string and I need it to actually be a variable name on the last line. How could I do this?

Burhan Khalid · Accepted Answer · 2014-04-13 04:45:04Z

1

What you have written will work, but you are overwriting the value in the assignment, since you repeat var. Instead, collect the results in a list:

def post(self):
    var_list = ['var1', 'var2']
    result_list = []
    for var in var_list:
        result_list.append(self.request.get(var))
    return result_list # etc.

You can further simplify it by using a list comprehension:

def post(self):
    return [self.request.get(var) for var in ['var1', 'var2']]

answered Apr 13, 2014 at 4:45

Burhan Khalid

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2 Comments

SethMMorton Over a year ago

Or, they could put it in a dict.

Burhan Khalid Over a year ago

@SethMMorton request.get seems to be a dict-like object already, so not sure what would be the point of that.

0x90 · Accepted Answer · 2014-04-13 04:48:20Z

0

Define MAX_VAR_NUM and use the following:

MAX_VAR_NUM=1000
var = [self.request.get("var"+str(i)) for i in xrange(1,MAX_VAR_NUM)]

You can add MAX_VAR_NUM as an attribute for the object instance:

var = [self.request.get("var"+str(i)) for i in xrange(1,self.max_var_num)]

answered Apr 13, 2014 at 4:48

0x90

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Comments

sshashank124 · Accepted Answer · 2014-04-13 04:56:09Z

0

Why not use a list instead:

def post(self):
    vars_list = []
    var_list = ['var'+str(i) for i in range(1,10)]
    for var in var_list:
        vars_list.append(self.request.get(var))

edited Apr 13, 2014 at 4:56

answered Apr 13, 2014 at 4:44

sshashank124

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1 Comment

msvalkon Over a year ago

You're overwriting the builtin vars()

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