On: Merging Maps

[ivan_ah]

Why not use `update` in Python? e.g. if you want to merge dictA and dictB, you'd write

    dictA.update(dictB)

If you have many you can always use this:

    dictD = {}
    map(dictD.update, [dictA, dictB, dictC])

[vanni → ivan_ah]

Or

    dictAB = dict(dictA, **dictB)

in Python 2 and 3.

[dom0 → vanni]

That'll create an intermediate dict (due to the unpacking) for Python <3.6 and then another dict. a.update(b) does neither.

It also has different semantics from a.update(b). The unpacking way will explode when both a and b contain the same key, while a.update(b) does not; existing keys also contained in b will be overwritten by the values from b.