Documentation doesn't specify how "new style" formatting works for complex numbers

[skirpichev]

Old string formatting has no support for complex numbers:

>>> "%f" % (1+0j)
Traceback (most recent call last):
  File "<python-input-0>", line 1, in <module>
    "%f" % (1+0j)
    ~~~~~^~~~~~~~
TypeError: must be real number, not complex

But formatted string literals and str.format() have:

>>> f"{1+0j:f}"
'1.000000+0.000000j'
>>> f"{1+0j:}"
'(1+0j)'
>>> f"{1.:}"  # default formatting slightly different than for floats
'1.0'

Unfortunately, formatting rules for complexes aren't documented in the Format Specification Mini-Language section. I'll work on a patch.

Linked PRs

• gh-122767: document "new style" formatting for complexes #122848
• [3.13] gh-122767: document "new style" formatting for complexes (GH-122848) #126128
• [3.12] gh-122767: document "new style" formatting for complexes (GH-122848) #126129