Feature Proposal: Multi-String Replacement Using a Dictionary in the .replace() Method

[blhsing (Ben Hsing)]

@ncoghlan

By analogy with .format and .format_map, this could be called .replace_map.

I personally would’ve slightly preferred .format to take a mapping with a second signature but yeah a separate function/method is just fine in the end of day.

Historically, this couldn’t be done because the order of application in the presence of overlapping patterns (or patterns that included later patterns in their output) would have been unpredictable when passing a built-in dict.

Thanks for the historical insight. The order does matter when keys in the input are inclusive of another. For example, with {'a': 'b', 'ab': 'c'}, 'abc' would be become 'bbc', but with {'ab': 'c', 'a': 'b'} it would become 'cc'.

@ncoghlan

These days, dicts are insertion ordered, so the method can safely be defined as equivalent to:

modified = original
for k, v in replacements.items():
    modified = modified.replace(k,v)

This code isn’t quite equivalent to what is proposed because it wouldn’t support swapping as @Rosuav mentioned.