Matthes E. Python Crash Course.a Hands-on-..pro... -

It was 1:57 a.m. The “Q3 Customer Retention Report” was due at 8 a.m., and her manual method—copy, paste, formula, weep—had just failed spectacularly. The new intern had deleted the master macro. Her boss had taken a red-eye to Singapore. And somewhere in the server room, a fan was making a sound like a dying seagull.

Eric didn’t teach her loops first. He threw her into the fire.

“Don’t be sorry. Be curious . Now, let’s visualize this. Chapter 15—plotting with Matplotlib. Make it ugly. We’ll fix it later.” Matthes E. Python Crash Course.A Hands-On-..Pro...

Lena slumped back. Her eyes landed on the book she’d bought three years ago, still pristine, still mocking her from the corner of her desk: .

“Took you long enough.”

She hit “Run” one last time. The script executed in 1.2 seconds.

“Good. Now refactor it.”

By 3 a.m., she had loaded the data. By 4 a.m., she had filtered out the null values that had been crashing Excel. By 5 a.m., Eric had her writing a function to calculate retention cohorts—something her boss paid a consultant $20,000 to do last year.