As an example: diameter = 7
next is where I would want to give the a value a variable name of 77 = 21
In python, is there any way of creating a variable that has the name of a value of another variable?
Asked
Active
Viewed 43 times
-2
-
Are you trying to make `7` equal to `21`? Reminds me of [this](http://meta.stackexchange.com/a/9182/311398) where Jon makes 3 equal to 1. – Bhargav Rao Feb 15 '16 at 12:37
-
5`7` is not a valid variable name – hjpotter92 Feb 15 '16 at 12:37
-
you can't make `7` the name of a variable – Sнаđошƒаӽ Feb 15 '16 at 12:41
-
Values in Python don't have names; namespaces hold names (which are, in general, just strings that are permitted names) and refer to objects. Since 7 is an integer literal in the language, it will never reach a name lookup. – Yann Vernier Feb 15 '16 at 12:53
2 Answers
2
Yes you can do it by modifying locals():
my_var = 'vla'
locals()[locals()['my_var']] = 'some_value'
# or use setdefault if you don't wan't to override variable if it already exist
locals().setdefault(locals()['my_var'], 'some_value')
print vla
# some_value
NOTE: value of my_var should be a valid python variable name. Which is the uppercase and lowercase letters A through Z, the
underscore _ and, except for the first character, the digits 0 through 9 ( shortly use pattern /[a-z_][a-z0-9_]*/i as @hjpotter suggested).
For your case you have to add some prefix before creating new variable from value, because your value is invalid variable name, see code below:
diameter = 7
# diameter value is invalid name for our new variable,
# let's add `_` prefix to value to be sure name is valid:
locals()['_' + str(locals()['my_var'])] = 'some_value'
# Note that i've applied str function to value of diameter variable
# to avoid TypeError (cannot concatenate 'str' and 'int' objects)
Andriy Ivaneyko
- 15,838
- 3
- 43
- 65
1
No. If you are attempting to assign a value to a numeral, that is not valid. Variable names must:
Start with either a letter or an underscore like:
_varname varnameNumerals may exist in the remainder of the variable name like:
_varname1 varname1
As a side note, variables are case sensitive too. Thus varname and Varname are two different variables.
A bit more detail can be found in this (non-python specific) question about why variables can't start with a number.
