Course outline

01 · Getting Started

02 · Variables, Types & Control Flow

03 · Functions & Composite Types

04 · Methods, Interfaces & Errors

05 · Packages, Modules & Concurrency Intro

06 · Your First Real Program

07 · Testing & Debugging in Go

08 · Capstone — Ship a Real Tool

Stage 1 · Code

Packages, Modules & Concurrency Intro

Standard Library Tour

A working tour of the Go packages you will reach for every day — strings, time, os, io, net/http, and encoding/json.

8 min readProgramming Foundations (Go)Code

strings and strconv

The strings package provides searching, splitting, trimming, and replacing on string values. strconv converts between strings and numeric types.

Gostrings-and-strconv-in-action.go

33 linesLn 1, Col 1Go

time

The time package handles instants, durations, formatting, and parsing. time.Now() returns the current time; time.Duration represents elapsed time. Always use time.Duration for intervals — not raw integers.

Goworking-with-time.go

31 linesLn 1, Col 1Go

Go's time format uses the reference time `Mon Jan 2 15:04:05 MST 2006` (01/02 03:04:05PM '06 -0700). This specific timestamp is used as a template — each number maps to its position in the format.

os and io

os interacts with the operating system: environment variables, files, arguments, and signals. io provides the core reader and writer interfaces and helpers for combining them.

Goreading-env,-files,-and-combining-readers.go

34 linesLn 1, Col 1Go

net/http

net/http is a production-ready HTTP client and server in the standard library. It handles connection pooling, TLS, redirects, and request routing out of the box.

Goa-minimal-http-server-and-client.go

36 linesLn 1, Col 1Go

`http.HandleFunc` registers a handler on the default mux. `defer resp.Body.Close()` is essential — failing to close response bodies leaks connections. `log.Fatal` calls `os.Exit(1)` on error.

encoding/json

encoding/json converts between Go values and JSON. Struct field tags control the JSON key names. json.Marshal encodes; json.Unmarshal (or json.NewDecoder) decodes.

Gomarshal-and-unmarshal.go

32 linesLn 1, Col 1Go

Field tags control JSON behaviour: `json:"host"` sets the key name, `omitempty` skips the field when it is the zero value, and `json:"-"` completely excludes a field from marshalling. The `APIKey` is never included in JSON output.

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