Check if a string is equal with a variable name

Question

I want to know if it is possible to compare if a string is equal with a variable name. For example I have the following declaration:

S=['A']
A=[['C'],['A','c','C']]
C=[['a'],['b'],['d','D']]
D=['A','e']
M=[S,A,C,D]
temp=[]

and

temp.append(S[0])
if S[0] in M :
...

Therefore I need to check if a string is equal with a variable name. Is it possible to do this? Thanks.

Do you want to know if M contains a reference to the same list as what A refers to? Python names are mere references; what if there is a B that refers to the same list, for example? — Martijn Pieters
– Martijn Pieters, Commented Dec 21, 2013 at 15:12
I need this for left/right terminal sets at Formal Language. — dimmg
– dimmg, Commented Dec 21, 2013 at 15:30

Martijn Pieters · Accepted Answer · 2013-12-21 15:13:21Z

1

You'd have to derefence A first, using globals() for example:

if globals()[S[0]] in M:

However, you should rarely need to use this, however. Generally, you'd have such objects in a dictionary of your own, for example:

lists = {'A': [...], 'C': [...]}

and then you just test if S[0] in lists is True.

answered Dec 21, 2013 at 15:13

Martijn Pieters

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