Code Explainers

Code explainers tagged #iterators

rust 
use std::f64::consts::PI;
 
#[derive(Debug, Clone, Copy)]
pub struct LatLng {

Building geographic bounding boxes in Rust

geospatial value-types option
Intermediate 7 steps
rust 
use chrono::{Duration, NaiveDate};
 
#[derive(Debug)]
pub struct DateRange {

Parsing and iterating date ranges in Rust

error-handling iterators parsing
Intermediate 7 steps
rust 
use axum::{
    extract::{FromRef, FromRequestParts, State},
    http::{header::ACCEPT_LANGUAGE, request::Parts, StatusCode},
    response::{IntoResponse, Response},

A custom Accept-Language extractor in Axum

extractors internationalization http-headers
Advanced 8 steps
rust 
pub fn extract_quoted_fields(line: &str) -> Vec<String> {
    let mut fields = Vec::new();
    let mut current = String::new();
    let mut in_quotes = false;

Parsing quoted fields with a state machine in Rust

state-machine parsing string-processing
Intermediate 7 steps
rust 
use std::fs::File;
use std::io::{self, BufRead, BufReader};
use std::path::Path;
 

Streaming lines from a gzip file in Rust

iterators io-streaming decompression
Intermediate 6 steps
rust 
use std::collections::BTreeSet;
 
#[derive(Debug)]
pub enum FieldError {

Parsing a cron field in Rust

parsing error-handling enums
Intermediate 7 steps
javascript 
class LRUCache {
  constructor(capacity) {
    if (capacity < 1) throw new RangeError('capacity must be positive');
    this.capacity = capacity;

Building an LRU cache with a JS Map

lru-cache data-structures insertion-order
Intermediate 8 steps
rust 
use itertools::Itertools;
use std::cmp::Ordering;
 
#[derive(Debug, Clone)]

Merging sorted event streams with itertools

iterators merge deduplication
Intermediate 7 steps
typescript 
interface RunningStats {
  count: number;
  total: number;
  average: number;

Streaming running averages in TypeScript

generators streaming incremental-aggregation
Intermediate 6 steps
python 
from itertools import cycle
from collections import defaultdict
 
 

Round-robin task distribution in Python

round-robin iterators load-balancing
Intermediate 6 steps
rust 
pub fn normalize_path(input: &str) -> String {
    let is_absolute = input.starts_with('/');
    let has_trailing_slash = input.len() > 1 && input.ends_with('/');
    let mut stack: Vec<&str> = Vec::new();

Normalizing filesystem paths in Rust

string-processing stack path-manipulation
Intermediate 8 steps
rust 
use once_cell::sync::Lazy;
use regex::Regex;
 
static NON_ALPHANUMERIC: Lazy<Regex> = Lazy::new(|| Regex::new(r"[^a-z0-9]+").unwrap());

Building URL slugs in Rust

string-processing regex transliteration
Intermediate 8 steps
rust 
#[derive(Debug, Clone, PartialEq)]
pub enum Token {
    Number(f64),
    Plus,

How a tokenizer turns text into tokens

lexing enums iterators
Intermediate 8 steps
rust 
use std::collections::HashMap;
 
#[derive(Debug)]
pub struct RequestHead {

Parsing an HTTP request head in Rust

parsing error-handling iterators
Intermediate 9 steps
rust 
use std::collections::HashMap;
 
fn decode_component(input: &str) -> String {
    let bytes = input.as_bytes();

Parsing a URL query string in Rust

url-encoding byte-parsing iterators
Intermediate 8 steps
rust 
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum FileKind {
    Png,
    Jpeg,

Detecting file types by magic bytes in Rust

pattern-matching byte-slices lookup-table
Intermediate 7 steps
php 
<?php
 
namespace App\Support;
 

Recursively finding files with SPL iterators in PHP

recursion iterators filesystem
Intermediate 7 steps
rust 
use axum::{
    extract::FromRequestParts,
    http::{request::Parts, StatusCode, header::ACCEPT_LANGUAGE},
};

A locale extractor for Axum handlers

content-negotiation http-headers custom-extractor
Intermediate 7 steps