Steven D'Aprano
How do dict displays construct the dict? Do they add keys from left to right, or right to left? I can read the source, if I can find it, and locate the right section of the right file, and if I can read C. Or I can do:
py> {1: "left", 1: "right"} {1: 'right'}
and in one line of code in the Python interactive interpreter I've learned more than in probably an hour of digging through C code.
The language reference explicitly says that the order from left to right and duplicate keys are also explicitly supported [1]: If a comma-separated sequence of key/datum pairs is given, they are evaluated from left to right to define the entries of the dictionary: each key object is used as a key into the dictionary to store the corresponding datum. This means that you can specify the same key multiple times in the key/datum list, and the final dictionary’s value for that key will be the last one given. [1] https://docs.python.org/3/reference/expressions.html#dictionary-displays Akira