2

I need to check variables looking like this:

if name1 != "":
    (do something)

Where the number right after "name" is incremented between 1 and 10.

Do I need to write the test ten times or is there a way (without using an array or a dict) to "concatenate", so to speak, variable names?

I'm thinking about something like this:

for i in range(10):
    if "name" + str(i) != "":
        (do something)

Edit: I can't use a list because I'm actually trying to parse results from a Flask WTF form, where results are retrieved like this:

print(form.name1.data)
print(form.name2.data)
print(form.name3.data)
etc.
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4
  • 1
    You use a list to hold your values, not ten different variables! Commented Apr 27, 2016 at 19:15
  • 1
    Is there a reason you can't use a list or a dict for this? It would be the most straightforward solution Commented Apr 27, 2016 at 19:16
  • 7
    @Rodolphe You should explain why you can't use a list. This just sounds like the XY problem. In almost all cases, using eval to do something like this means you have a terrible software design issue. Commented Apr 27, 2016 at 19:21
  • In the specific case where there are already existing attributes of an object like form.name1, form.name2 etc. and you can't modify the code (e.g. to make form.name be a list of those values), the appropriate tool is getattr. I have added an appropriate duplicate. In general, use a list or dictionary to avoid the problem. Commented Jul 4, 2022 at 22:58

3 Answers 3

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4

  1. Use a list, such as:

    names = ['bob', 'alice', 'john']

    And then iterate on the list:

    for n in names:
  if n != "":
     (do something)

  2. or you could have a compounded if statement:

    if (name1 != "" or name2 != "" or name3 != "")

The best solution would be to use solution #1.

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1 Comment

I can't use a list unfortunately... but thanks!
3

If you cannot use a list or a dict, you could use eval

for i in range(10):
    if eval("name" + str(i)) != "":
        (do something)
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0

First of all, your app have invalid logic. You should use list, dict or your custom obj.

You can get all variable in globals. Globals is a dict.

You can do next:

for i in range(10):
    if globals().get('name%d' % i):
        # do something
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