Create dictionary where keys are variable names

Question

I quite regularly want to create a dictionary where keys are variable names. For example if I have variables a and b I want to generate: {\"a

Answer 1

You can write your own function for create_dict

def create_dict(*args):
  return dict({i:eval(i) for i in args})

a = "yo"
b = 7
print (create_dict("a", "b"))

Which gives {'a': 'yo', 'b': 7} output.
Here's a simple generator for the same:

vars = ["a", "b"]
create_dict = {i:eval(i) for i in args}

or you can use this one-liner lambda function

create_dict = lambda *args: {i:eval(i) for i in args}
print (create_dict("a", "b"))

But if you want to pass the variables to the function instead of the variable name as string, then its pretty messy to actually get the name of the variable as a string. But if thats the case then you should probably try using locals(), vars(), globals() as used by Nf4r

Answer 2

Extending on the code of @Nf4r, I use something like:

a, b = 1, 2

def make_dict(*args):
    # Globals will change of size, so we need a copy
    g = {k: v for k, v in globals().items() if not k.startswith('__')}  

    result = {}
    for arg in args:
        for k, v in g.items():
            try:
                if v == arg:
                    result[k] = v
            except ValueError:
                continue  # objects that don't allow comparison

    return result

make_dict(a, b)

Answer 3

Have you considered creating a class? A class can be viewed as a wrapper for a dictionary.

# Generate some variables in the workspace
a = 9; b = ["hello", "world"]; c = (True, False)

# Define a new class and instantiate
class NewClass(object): pass
mydict = NewClass()

# Set attributes of the new class
mydict.a = a
mydict.b = b
mydict.c = c

# Print the dict form of the class
mydict.__dict__
{'a': 9, 'b': ['hello', 'world'], 'c': (True, False)}

Or you could use the setattr function if you wanted to pass a list of variable names:

mydict = NewClass()
vars = ['a', 'b', 'c']
for v in vars: 
    setattr(mydict, v, eval(v)) 

mydict.__dict__
{'a': 9, 'b': ['hello', 'world'], 'c': (True, False)}

Answer 4

Have you tried something like:

a, b, c, d = 1, 2, 3, 4
dt = {k:v for k, v in locals().items() if not k.startswith('__')}
print(dt)
{'a': 1, 'd': 4, 'b': 2, 'c': 3}