String formatting [str.format()] with a dictionary key which is a str() of a number
python, python-2.7
Solution
No. According to the documentation:
Because arg_name is not quote-delimited, it is not possible to specify arbitrary dictionary keys (e.g., the strings '10' or ':-]') within a format string.
So you can't use strings consisting of numbers as dictionary keys in format strings.
Note that your key isn't numeric, and it's not trying to use it as a list index. Your key is a string that happens to contain a digit character. What it's trying to do is use the number 1 (not the string "1") as a dictionary key. It will work if you use the number 1 as your dictionary key (i.e., make your dict `{'key1': 'val1', 1: 'val2'}`).
Problem
Python neophyte here. I was wondering if someone could help with the `KeyError` I am getting when using a dictionary for string interpolation in `str.format`. ``` dictionary = {'key1': 'val1', '1': 'val2'} string1 = 'Interpolating {0[key1]}'.format(dictionary) print string1 ``` The above works fine and yields: ``` Interpolating val1 ``` However doing the following: ``` dictionary = {'key1': 'val1', '1': 'val2'} string2 = 'Interpolating {0[1]}'.format(dictionary) print string2 ``` results in: ``` Traceback (most recent call last): File "test.py", line 3, in <module> string2 = 'Interpolating {0[1]}'.format(dictionary) KeyError: 1L ``` So the problem seems to be in the interpretation of the numeric key as a list index, IMHO. Is there any way to work around this? (i.e. convey that this is instead a dictionary key) TIA and apologies if this question has been asked before(couldn't find anything relevant with my search-fu). Edit 1: The key is not numeric as was erroneously noted, earlier. Instead it is a string representation of a number - as was pointed out by BrenBarn.