Programming Tutorials and Coding Guides

Learn what FileNotFoundError (No such file or directory, errno 2) means in Python, why it happens even when the file seems to exist, and how to fix it with correct paths, working directory, pathlib, symlinks, and …

Terminate processes from Go by PID or child PID: os.Process and os.FindProcess, Process.Kill vs Process.Signal (SIGTERM vs SIGKILL), stopping commands started with os/exec, timeouts with exec.CommandContext, graceful …

Learn how to concatenate tensors in PyTorch with torch.cat along dim 0 or 1, torch.concat and torch.concatenate aliases, shape rules, stack vs cat, device errors, and a quick reference table.

strconv in Go: parse and format integers, floats, and bools, Quote and Unquote, bases with FormatUint and ParseInt, NumError with errors.Is, and when to prefer strconv over fmt.Sscanf.

strings.Contains for literal UTF-8 substrings, case sensitivity and ToLower, match any or all needles, ContainsAny and ContainsRune, Index and HasPrefix or HasSuffix, empty substring behavior, and regexp only when you …

Golang SHA-512 with crypto/sha512: Sum512 and hex, sha512.New streaming io.Copy, file checksum verify, streams vs one-shot, salt-and-hash demo with verification caveats, SHA-512 vs SHA-256, HMAC, use cases, passwords …

Compare strings in Go with == and !=, lexicographic order with < and >, strings.EqualFold for case-insensitive match, strings.Compare for three-way results, and trimming input before comparing.

Read command-line arguments in Go with os.Args, use the flag package for named options, validate positional args, parse numbers safely, and understand go run vs a compiled binary.

Learn what ampersand means in Go, how & gets a variable address, how * works with pointers, and how & and * are used together in simple examples.

Learn variable scope in Go, including local variables, package-level variables, global-style variables, block scope, short declarations, shadowing, and best practices.

Learn why Go uses underscore before an import path, how blank imports work, when packages are imported for side effects, and how this relates to unused import errors.

Learn how to build a Go web server using net/http, configure routes, handlers, ports, timeouts, static files, JSON responses, and graceful shutdown.

Learn closures in Go: function values that capture outer variables, how they differ from anonymous functions, returned functions and state, goroutine loop pitfalls, and golang closure performance and escape analysis.

Learn how to use sync.WaitGroup in Go to wait for goroutines, with Add, Done, Wait, WaitGroup.Go, common mistakes, and practical examples.

Learn buffered channels in Go: make(chan T,n) capacity, len and cap, when send and receive block, buffered vs unbuffered channels, backpressure, deadlocks, choosing buffer size, and practical patterns.

Learn how to import a local Go package without GOPATH using go.mod, module paths, subfolders, exported names, replace directives, and go.work.

Golang SHA-256 with crypto/sha256: Sum256 and hex, sha256.New streaming io.Copy, file checksums and verification, compare files, subtle comparison, HMAC sign/verify, MD5 vs SHA-1 vs SHA-256, passwords use bcrypt; quick …

Learn how multiple goroutines read from the same Go channel: each value is received once, fan-out worker pools, closing rules, result channels, buffered vs unbuffered, and why this is not broadcast.

Learn how to use regex in Go with the regexp package, including MatchString, Compile, MustCompile, FindString, submatches, ReplaceAllString, Split, and common mistakes.

Learn how to check if a Go slice contains a value, find the index of an element, search by condition with IndexFunc, and choose between slices, loops, and maps.

Understand the difference between goroutines and OS threads in Go, how the Go runtime scheduler maps goroutines onto threads, and why goroutines are lightweight.

Learn anonymous structs in Go: inline struct syntax, JSON tags, slices and maps, returning unnamed struct types, why methods attach to named types, embedding vs anonymous fields, and when to use a named struct.

Golang import local package and go import local package with Go modules: golang import package from another directory under the module root, golang use local package and golang local package import paths, golang import …

Golang function guide: overview, syntax and naming, declaring and calling, single and multiple returns, errors and pointers, pass by value vs pointer, struct map slice channel, variadic pointer to variadic article, …

Learn the fan-out fan-in pattern in Go with goroutines and channels: distribute work, merge results, relate it to worker pools, handle errors and cancellation, preserve ordering when needed, and close channels safely.

Compare popular Go web frameworks including Gin, Echo, Fiber, Chi, Beego, and net/http. Learn which framework fits REST APIs, microservices, web apps, and high-performance services.

Golang byte to int: uint8 widening, []byte ASCII to int with strconv.Atoi and validated ParseInt, math/big SetBytes for long unsigned magnitudes, encoding/binary Uint32 Uint64 and Read for int32, reverse int64 to []byte …

Golang http and go http with net/http: golang http server example using ListenAndServe and ServeMux, golang https server and https golang with http.ListenAndServeTLS, golang http module meaning the standard library …

Golang portping with janosgyerik/portping: set up module, Ping and PingN API, sequential and parallel TCP checks, port ranges, PingN result handling, retries, per-dial timing, CLI install, common dial errors; links to …

Trim strings in Go with strings.TrimSpace, strings.Trim, TrimPrefix, and TrimSuffix to remove whitespace, cutset characters, and exact prefixes or suffixes.