Yes, Los Angeles has a subway. And it's growing.
The above-ground Expo Line—much of which was built along an old Pacific Electric right-of-way—became the "Subway to the Sea" when it fully opened between Culver City and Santa Monica in 2016. (It's now, however, called the E line.)
The Purple Line Extension will put a subway station about a mile and a half away from where I live sometime in the next three or four years. (The Purple Line has also been renamed the D Line but I haven't fully committed to calling the lines by their letters instead of their colors yet.)
Until then, if I want to ride the subway, I've got to make a special trip.
Last weekend, I trekked downtown just to check out three just-opened subway stations that comprise the Metro Regional Connector project—which allows seamless transit from Long Beach to Azusa and Santa Monica to East Los Angeles along the A and E lines.