Lua:
Converting a date into a string

How to:

In Lua, we use os.date to format dates into strings. Here’s a slice of code to chew on.

local now = os.time()
local formatted = os.date("%Y-%m-%d %H:%M:%S", now)
print(formatted)
-- Example output: 2023-04-01 15:24:37

Want a different flavor? Customize the string pattern.

local friendly_format = os.date("%B %d, %Y")
print(friendly_format)
-- Example output: April 01, 2023

Deep Dive

Lua’s os.date function is modeled after the POSIX strftime function. If you squint, you’ll notice it’s similar to C’s printf family—same roots.

Alternatives? Sure. You could wrestle with string concatenation and table indexing—manually grabbing date parts. But why sweat when os.date handles it?

Implementation details? The os.date function can behave in two ways:

• Given a format string, it returns the formatted date.
• Omit the format, and it returns a table with date components.

Fun fact: Lua’s time-related functions use the epoch as reference—the number of seconds since Jan 1, 1970. This quirk traces back to Unix time.

See Also

• Lua’s reference manual on os.date: https://www.lua.org/manual/5.4/manual.html#pdf-os.date
• strftime format specifiers to spice up os.date: http://strftime.org/
• A dive into Unix epoch time for the curious: https://en.wikipedia.org/wiki/Unix_time