Companies cannot hire fast enough. Glassdoor, an employment site, lists more than 7,300 openings for software engineers, ahead of job openings for nurses, who are chronically in short supply. For the smaller category of data scientists, there are more than 1,200 job openings. Demand is highest in San Francisco. Nationally, the average base salary for software engineers is $100,000, and $112,000 for data scientists.

In March, the White House announced an initiative, TechHire, to coordinate the efforts of the federal government, cities, corporations and schools to train workers for the thousands of current job openings in the tech sector. The Obama administration points to coding schools like Galvanize, Flatiron School and Hack Reactor, which offer accelerated training in digital skills as a way to “rapidly train workers for a well-paying job.”

The graduating classes of these coding schools support the trend. They will graduate about 16,000 students this year, more than double the 6,740 graduates last year, according to a survey published by Course Report in June. The 2015 total would be about one-third of the estimated number of computer science graduates from American universities. The largest concentration of the schools, often called boot camps, is in San Francisco, which has 12, followed by New York, with nine, and Seattle, eight.

Students are of a wide age range, but most are in their 20s and 30s. The typical student is a “29-year-old career changer,” said Liz Eggleston, co-founder of Course Report, which tracks these schools.