np.set_printoptions doesn't affect floats

>>> import numpy as np
>>> '%s' % np.array(1/3)
'0.3333333333333333'
>>> '%s' % np.array([1/3])
'[0.33333333]'
>>> np.set_printoptions(formatter={"float_kind": lambda x: "%.1f" % x})
>>> '%s' % np.array(1/3)
'0.3333333333333333'
>>> '%s' % np.array([1/3])
'[0.3]'

[eric-wieser]

A simpler reproduction is:

>>> np.set_printoptions(formatter={"float_kind": lambda x: "%.1f" % x})
>>> str(np.float64(1/3))
str(np.float64(1/3))

@ahaldane, do you think this is a feature (full precision is always shown for scalars) or an omission?

[ahaldane]

For the record, this behavior goes back as far as numpy 1.0.1, and probably before.

#9201 shows our attempts to update the str/repr of 0d arrays and why we had to keep this behavior. As I recall it was due to people expecting that str applied to a 0d array of S or U dtype would always give back the string itself.