Dynamically defining variables from a dictionary

Question

I am trying to dynamically define variables from a dictionary in python. I need my variables to be strings, they should appear something like this: lightgreen = "#2ecc71". To do this I added HEX_VALUE = "'" + HEX_VALUE + "'" however adding this I encountered an error

> Traceback (most recent call last):
line 22, in <module>
    exec("%s=%s" % (COLOUR_NAME, HEX_VALUE))
  File "<string>", line 1
    darkblue:='#2980b9'
            ^
SyntaxError: invalid syntax

As seen from above, this adds ':' to the first part of the variable, so my question is: how can I prevent this?

COLOURS = {
    "lightgreen":"'#2ecc71'",
    "darkgreen":"#27ae60",
    "lightblue":"#3498db",
    "darkblue:":"#2980b9",
    "lightpurple":"#e74c3c",
    "darkpurple":"#8e44ad",
    "lightred":"#e74c3c",
    "darkred":"#c0392b",
    "lightorange":"#e67e22",
    "darkorange":"#d35400",
    "lightyellow":"#f1c40f",
    "darkyellow":"#f39c12",
    "lightteal": "#1abc9c",
    "darkteal": "#16a085",
    "lightnavy": "#34495e",
    "darknavy": "#2c3e50"
    }

for COLOUR_NAME, HEX_VALUE in COLOURS.items():
    HEX_VALUE = "'" + HEX_VALUE + "'"
    exec("%s=%s" % (COLOUR_NAME, HEX_VALUE))

Y u need to define the variable. Just use `COLOURS.get(key)` to access the value? — Abdul Niyas P M, Mar 16 '18 at 12:53
I'll never understand why people try to do so much gymnastics to define variables. You have a perfectly good `dict` of your colors, just use that directly! — Cory Kramer, Mar 16 '18 at 12:54
@CoryKramer it's just inexperience with the common datastructures and their usage. — timgeb, Mar 16 '18 at 13:00

score 4 · Answer 1 · answered Mar 16 '18 at 13:03

As some mentioned in the comments, there is no reason to use exec to make python define new variables. The hex values are already strings in the dictionary so you can just access them directly like so:

lightgreen = COLOURS["lightgreen"]

Although I'll not there is no reason to define variables with the same name as the key of the dict since the dict can just always be accessed directly when necessary.

Dynamically defining variables from a dictionary

1 Answers1