I know this is an electrical engineering convention, but I'm still wondering why it was chosen for Python. I don't know other programming languages with complex-number literals, so I don't have anything to compare against, but does anyone know any that do use i?
i in electrical engineering is typically used for i(t) or instantaneous current. I is for steady state  DC (non-complex)  or rms values of AC current.  In addition  spacial coordinates are generally expressed as i,j,k  but for two dimensional items i,j are all that are needed and the "i" is dropped so the  perpendicular "j" is used  as in 4j3 vs 4+3i or 4i3 -See that this is  not 413 at a glance.
J recognizes this notation in handling complex numbers. As a retired EE prof- I do like the use of "j"  As for Current density "J" is used.
Why are complex numbers in Python denoted with 'j' instead of 'i'?