List user defined variables, python

Question

I am trying to iterate through the variables set in a python script. I came across the following:

Enumerate or list all variables in a program of [your favorite language here]

and in the first example:

#!/us/bin/python                                                                                    

foo1 = "Hello world"
foo2 = "bar"
foo3 = {"1":"a", "2":"b"}
foo4 = "1+1"

for name in dir():
    myvalue = eval(name)
    print name, "is", type(name), "and is equal to ", myvalue

It lists all the variables stored in memory. I want to isolate the variables I have created in my script and not list the system variables created by default. Is there any way to do this?

possible duplicate of How to get a list of variables in specific Python module? — Ignacio Vazquez-Abrams
– Ignacio Vazquez-Abrams, Commented Apr 24, 2012 at 16:43

mrmagooey · Accepted Answer · 2012-07-08 05:17:17Z

10

If you don't put any underscores in front of your variables you could do:

#!/us/bin/python                                                                                    

foo1 = "Hello world"
foo2 = "bar"
foo3 = {"1":"a", "2":"b"}
foo4 = "1+1"

for name in dir():
    if not name.startswith('__'):
        myvalue = eval(name)
        print name, "is", type(myvalue), "and is equal to ", myvalue

edited Jul 8, 2012 at 5:17

mrmagooey

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answered Apr 24, 2012 at 16:41

Niek de Klein

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Comments

jterrace · Accepted Answer · 2012-04-24 16:52:21Z

9

You can strip out variables that are included in your module by default by checking if they are in the builtin __builtins__ module, like this:

>>> x = 3
>>> set(dir()) - set(dir(__builtins__))
set(['__builtins__', 'x'])

The only thing this doesn't strip out is __builtins__ itself, which is easy to special case.

Also note that this won't work if you have re-defined any builtin names. You shouldn't do this in practice, but a lot of people do, many by accident.

edited Apr 24, 2012 at 16:52

answered Apr 24, 2012 at 16:45

jterrace

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3 Comments

interjay Over a year ago

dir() doesn't give the names in __builtins__ for me (Python 2.7). All I get is ['__builtins__', '__doc__', '__name__', '__package__'].

jterrace Over a year ago

@interjay it gives some other things though, like __doc__ and __name__ that I think OP wants stripped out

interjay Over a year ago

But that has nothing to do with __builtins__, they are just names which are defined in every module (and therefore happen to be in __builtins__ as well). Calling them "builtin variables" is misleading.

akaRem · Accepted Answer · 2012-04-24 18:29:51Z

2

Here is solution.

#!/us/bin/python    

not_my_data = set(dir())

foo1 = "Hello world"
foo2 = "bar"
foo3 = {"1":"a", "2":"b"}
foo4 = "1+1"

my_data = set(dir()) - not_my_data

for name in my_data :
    myvalue = eval(name)
    print name, "is", type(name), "and is equal to ", myvalue

but this is bad practice.

You should use something like

#!/us/bin/python    
my_data = dict()                                                                                   
my_data['foo1'] = "Hello world"
my_data['foo2'] = "bar"
my_data['foo1'] = {"1":"a", "2":"b"}
my_data['foo1'] = "1+1"

for name in my_data :
    myvalue = eval(my_data[name])
    print name, "is", type(name), "and is equal to ", myvalue

answered Apr 24, 2012 at 18:29

akaRem

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Comments

hajunho · Accepted Answer · 2020-11-23 00:13:03Z

1

The question title leads me to see this. But this is not what I wanted.

self-answering is below

[s for s in dir() if not '__' in s]

answered Nov 23, 2020 at 0:13

hajunho

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Comments

Dan Steingart · Accepted Answer · 2014-10-22 16:28:38Z

I wanted something more along the lines of matlab 'whos', so I baked this up: gist here

import __main__
def whos(lss):
 fil = __main__.__file__
 thisthinghere = open(fil).read().split("\n")
 vs = []
 for l in thisthinghere:
    if l.find("=") > -1:
        vs.append(l.split("=")[0].strip())
 keys = lss.keys()
 out = {}
 for v in vs:
    try: 
        out[v] = lss[v]
    except:
        "not in list"
 keys = out.keys()
 keys.sort()
 for k in keys:
    val = str(out[k])
    if len (val) > 10:
        if val[-1] == ")":val = val[0:10]+"..."+val[-10:]
        elif val[-1] == "]" :val = val[0:10]+"..."+val[-10:]
        else: val = val[0:10]
    print k,":",val

 return out

#import into your script and call with whos(locals())

it seems to work. it will print the variable space, and it returns it as a dictionary for easy pickling/jsoning.

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