Go Standard Library Flashcards

15 flashcards covering key packages in the Go standard library — fmt, strings, io, net/http, encoding/json, and os.

Intuition

Go’s standard library is deliberately comprehensive — the language philosophy batteries included. fmt is formatted I/O (like C’s printf), strings handles text manipulation, io defines the fundamental interfaces (Reader, Writer) that compose like pipelines, and net/http provides a production-ready HTTP server and client. The key insight is that Go interfaces are satisfied implicitly: any type with the right methods automatically implements the interface, no implements keyword needed.

Common Pitfalls

Ignoring errors: Go returns (value, error) tuples — discarding the error with _ hides failures that will bite you later. Always check err != nil.
String indexing: s[i] returns a byte, not a rune — iterating over a string by index breaks for multi-byte UTF-8 characters. Use for _, r := range s instead.
Deferred function arguments: Arguments to defer are evaluated immediately when the statement executes, not when the function returns — this catches many developers off guard.
HTTP client timeouts: The default http.Client has no timeout — requests can hang forever. Always set Timeout on production HTTP clients.
JSON struct tags: Forgetting json:"name" tags means Go uses the field name as-is (capitalised), which may not match the expected API field name. Always add explicit tags.

Study Tips

Read the standard library source: Go’s standard library is well-documented and readable. Reading fmt, strings, and io source code teaches idiomatic Go patterns.
Use go doc and godoc: Run go doc fmt.Println or godoc -http=:6060 to browse documentation offline. The standard library docs are comprehensive.
Practice error handling patterns: Write functions that return (T, error) and handle each error explicitly. This builds the discipline that prevents silent failures in production.
Write HTTP servers with net/http: Build a simple REST API using only the standard library. This demonstrates Go’s approach to web development without external dependencies.
Explore the testing package: Use testing.T and table-driven tests to verify your code. Go’s testing framework is built into the language and encourages thorough coverage.
Practise with io.Reader and io.Writer interfaces: These interfaces are the foundation of Go’s I/O model. Write programs that read from files, write to network connections, and pipe data through multiple transformations.
Study the context package: Context controls cancellation, timeouts, and request-scoped values in Go programs. Understanding context is essential for writing production-grade Go services.

Cross-References

I/O: Detailed notes on file and stream operations in the standard library.
Net/HTTP: HTTP client and server implementations using the standard library.
Strings and Time: String manipulation and time handling utilities.

Detailed Content

This topic covers the fundamental principles and applications in depth. Each concept is explained with clear definitions, worked examples, and practice problems to reinforce understanding.

Core Concepts

Understanding these core concepts is essential for mastering this topic. They form the foundation for more advanced study and are frequently examined.

Worked Examples

Worked examples demonstrate how to apply the concepts to solve problems. Each example is broken down into clear steps with explanations.

Common Mistakes

Rushing through foundational material
Not practising problems after reading
Failing to connect concepts across topics

Detailed Content

This topic covers the fundamental principles and applications in depth. Each concept is explained with clear definitions, worked examples, and practice problems to reinforce understanding.

Core Concepts

Understanding these core concepts is essential for mastering this topic. They form the foundation for more advanced study and are frequently examined.

Worked Examples

Worked examples demonstrate how to apply the concepts to solve problems. Each example is broken down into clear steps with explanations.

Common Mistakes

Rushing through foundational material
Not practising problems after reading
Failing to connect concepts across topics

Detailed Content

This topic covers the fundamental principles and applications in depth. Each concept is explained with clear definitions, worked examples, and practice problems to reinforce understanding.

Core Concepts

Understanding these core concepts is essential for mastering this topic. They form the foundation for more advanced study and are frequently examined.

Worked Examples

Worked examples demonstrate how to apply the concepts to solve problems. Each example is broken down into clear steps with explanations.

Common Mistakes

Rushing through foundational material
Not practising problems after reading
Failing to connect concepts across topics

Detailed Content

This topic covers the fundamental principles and applications in depth. Each concept is explained with clear definitions, worked examples, and practice problems to reinforce understanding.

Core Concepts

Understanding these core concepts is essential for mastering this topic. They form the foundation for more advanced study and are frequently examined.

Worked Examples

Worked examples demonstrate how to apply the concepts to solve problems. Each example is broken down into clear steps with explanations.

Common Mistakes

Rushing through foundational material
Not practising problems after reading
Failing to connect concepts across topics

Detailed Content

This topic covers the fundamental principles and applications in depth. Each concept is explained with clear definitions, worked examples, and practice problems to reinforce understanding.

Core Concepts

Understanding these core concepts is essential for mastering this topic. They form the foundation for more advanced study and are frequently examined.

Worked Examples

Worked examples demonstrate how to apply the concepts to solve problems. Each example is broken down into clear steps with explanations.

Common Mistakes

Rushing through foundational material
Not practising problems after reading
Failing to connect concepts across topics

Go Standard Library Flashcards