Time and date

Time.now

Time dot now captures the current moment with date and clock time together. Print it during logging to see exactly when events happen.

Time objects compare with plain operators, so finding the later of two moments needs no extra library. Dates often arrive as text, so the string skills from Encodings pair well with this lesson.

now = Time.now puts now

Format with strftime

strftime turns a Time into text using percent codes for year, month, day, hours, and minutes. You arrange the codes with any separators you like.

One format string can serve logs, file names, and screen output without extra helpers.

t = Time.now puts t.strftime("%Y-%m-%d")

Parse input

The time library adds parsing of common formats. Require it first, then pass the user text to parse.

Invalid text raises an error, so validate around parsing when input comes from strangers.

require "time" t = Time.parse("2026-10-06") puts t.year

Date arithmetic

The date library adds calendar math without clock time. today gives the current date, and plus or minus a number shifts by days.

Subtracting two dates gives the gap between them, which to_i turns into whole days.

require "date" today = Date.today puts today + 7

Next: JSON and YAML

Article author: Arthur Isaev