How to harness Python as a programming language when you mostly know Excel
Most of the new juniors who get jobs in investment banks now know how to code a bit in Python. However, this doesn't mean they're Python natives, and typically they still spend a lot of time in Excel. One former product manager at UBS asset management has developed an open-source product to make their lives easier.
"The idea is to automate Excel with Python," says Felix Zumstein, an ex-UBS director and the man behind XLWings, a Python library that can be called from Excel using a syntax not dissimilar to VBA. "It's not for professional developers," says Zumstein of his creation. "It's for citizen developers, for people who spend an hour or so every day tinkering about in code and who know how to code a bit, but who mostly write a little bit of code as a means to an end."
Given that XLWings operates at the intersection of Python and Excel and that its protagonist came from a Swiss bank, it's unsurprising that most of its users are working in finance. "People using XLWings can be financial modelers, economists, anything in banking," says Zumstein. "It speeds up workflows. - If you just want to format a spreadsheet to look nice, it's not the ideal use case. But if you want to do scientific computations in Excel or calculations with a lot of data, it will make your life a lot easier."
Zumstein says users come from both ends of the age spectrum. On one hand, they're the "Excel guys aged 40+ who only really know VBA"; on the other, they're new analysts who can potentially do everything in Python but who use Excel when they need to send data to senior staff. "Excel will always be used in banks somewhere," says Zumstein. XLWings makes using it easier.
XLWings piggybacks on PyWin32. Zumstein began working on it in 2014. Today, there's a paid version that he sells to "major banks, hedge funds and S&P 500 companies" and an unpaid open-source version that's been downloaded nearly 650,000 times in the last 30 days alone.
Not all banks allow juniors to plug-in open-source packages, but Zumstein says smaller boutiques in particular are ahead of the curve and that some analysts use XLWings anyway: "It's become much more common to use open-source software packages than it used to be."
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