Python 数据结构:从官方教程到实战选型

users = ["alice", "bob", "carol"]users.append("dave")users.extend(["eric", "frank"])first = users[0]last_two = users[-2:]users.sort()

numbers = [3, 1, 2]result = numbers.sort()print(numbers)  # [1, 2, 3]print(result)   # None

raw_scores = [80, 95, 72]ranked = sorted(raw_scores, reverse=True)print(raw_scores)  # [80, 95, 72]print(ranked)      # [95, 80, 72]

stack = []stack.append("parse")stack.append("validate")stack.append("save")while stack:    step = stack.pop()    print(step)

def is_valid_parentheses(text: str) -> bool:    pairs = {")": "(", "]": "[", "}": "{"}    stack = []    for char in text:        if char in "([{":            stack.append(char)        elif char in pairs:            if stack == [] or stack.pop() != pairs[char]:                return False    return stack == []

from collections import dequequeue = deque(["task-1", "task-2"])queue.append("task-3")while queue:    task = queue.popleft()    print("handle", task)

squares = [x * x for x in range(10)]even_squares = [x * x for x in range(10) if x % 2 == 0]

raw_names = [" Alice ", "BOB", " carol"]names = [name.strip().lower() for name in raw_names]

matrix = [[1, 2, 3], [4, 5, 6]]flat = [num for row in matrix for num in row]

flat = []for row in matrix:    for num in row:        flat.append(num)

matrix = [    [1, 2, 3],    [4, 5, 6],]columns = list(zip(*matrix))

items = ["a", "b", "c", "d"]del items[0]del items[1:]

items = [1, 2, 3]del items[:]

cache = {"token": "abc"}del cache

profile = {"nickname": None, "age": 30}del profile["age"]      # age 这个字段被移除profile["nickname"] = None  # nickname 字段存在，值为空

point = (120.5, 31.2)x, y = point

def split_name(full_name: str) -> tuple[str, str]:    first, last = full_name.split(maxsplit=1)    return first, lastfirst, last = split_name("Ada Lovelace")

not_tuple = ("hello")one_item_tuple = ("hello",)

record = ([1, 2], "ok")record[0].append(3)print(record)  # ([1, 2, 3], 'ok')

sales = {    ("2026-07-14", "CN"): 1200,    ("2026-07-14", "US"): 900,}

tags = ["python", "web", "python", "ai"]unique_tags = set(tags)print("python" in unique_tags)

old_permissions = {"read", "write"}new_permissions = {"read", "delete"}added = new_permissions - old_permissionsremoved = old_permissions - new_permissionskept = old_permissions & new_permissionschanged = old_permissions ^ new_permissions

empty_set = set()empty_dict = {}

for tag in sorted(unique_tags):    print(tag)

def unique_in_order(items):    seen = set()    result = []    for item in items:        if item in seen:            continue        seen.add(item)        result.append(item)    return result

profile = {    "id": 1001,    "name": "Ada",    "role": "admin",}profile["active"] = True

nickname = profile.get("nickname", "匿名用户")

if "role" in profile:    print(profile["role"])

for key in sorted(profile):    print(key, profile[key])

users = ["alice", "bob", "carol"]index = {name: i for i, name in enumerate(users)}

rows = [    {"id": 1, "name": "Ada"},    {"id": 2, "name": "Guido"},]users_by_id = {row["id"]: row for row in rows}

for key, value in profile.items():    print(key, value)

for line_no, line in enumerate(lines, start=1):    print(line_no, line)

names = ["Ada", "Guido"]scores = [98, 95]for name, score in zip(names, scores):    print(name, score)

for item in reversed(history):    print(item)

for name in sorted(users):    print(name)

if errors:    print("存在错误")

if user_id in active_users:    ...

name = user.get("nickname") or user.get("name") or "匿名用户"

value = payload.get("count")if value is None:    value = 0

if result is None:    ...

(1, 2, 3) < (1, 2, 4)["a", "b"] < ["a", "c"]

records = [    {"name": "Ada", "score": 98, "time": 35},    {"name": "Guido", "score": 98, "time": 31},    {"name": "Linus", "score": 95, "time": 28},]ranked = sorted(records, key=lambda r: (-r["score"], r["time"]))

from collections import dequerecent = deque(maxlen=3)for event in ["login", "click", "pay", "logout"]:    recent.append(event)print(list(recent))  # ['click', 'pay', 'logout']

from collections import dequedef moving_average(values, window_size):    window = deque()    total = 0    for value in values:        window.append(value)        total += value        if len(window) > window_size:            total -= window.popleft()        yield total / len(window)

from collections import Counterstatus_codes = [200, 200, 404, 500, 200, 404]counter = Counter(status_codes)print(counter[403])          # 0print(counter.most_common(2)) # [(200, 3), (404, 2)]

from collections import Counterinventory = Counter(apple=5, banana=2)order = Counter(apple=3, banana=4)available = inventory - ordermissing = order - inventory

from collections import defaultdictorders = [    {"user": "alice", "amount": 80},    {"user": "bob", "amount": 50},    {"user": "alice", "amount": 20},]amounts_by_user = defaultdict(list)for order in orders:    amounts_by_user[order["user"]].append(order["amount"])

total_by_user = defaultdict(int)for order in orders:    total_by_user[order["user"]] += order["amount"]

graph = defaultdict(list)graph["A"].append("B")graph["A"].append("C")

import heapqscores = [90, 75, 98, 82, 100, 88]top3 = heapq.nlargest(3, scores)

import heapqtasks = []heapq.heappush(tasks, (2, "send email"))heapq.heappush(tasks, (1, "write report"))heapq.heappush(tasks, (3, "archive logs"))while tasks:    priority, task = heapq.heappop(tasks)    print(priority, task)

from collections import Counter, defaultdictimport heapqlogs = [    {"user": "u1", "path": "/api/orders", "status": 200, "ms": 120},    {"user": "u2", "path": "/api/orders", "status": 500, "ms": 860},    {"user": "u1", "path": "/api/profile", "status": 200, "ms": 90},    {"user": "u3", "path": "/api/orders", "status": 404, "ms": 210},]active_users = {row["user"] for row in logs}by_path = defaultdict(list)for row in logs:    by_path[row["path"]].append(row)status_counter = Counter(row["status"] for row in logs)slowest = heapq.nlargest(2, logs, key=lambda row: row["ms"])print(active_users)print(status_counter.most_common())print(slowest)

rows = [[1, 2], [3, 4]]copied = rows.copy()copied[0].append(99)print(rows)    # [[1, 2, 99], [3, 4]]print(copied)  # [[1, 2, 99], [3, 4]]

from copy import deepcopyrows = [[1, 2], [3, 4]]copied = deepcopy(rows)copied[0].append(99)print(rows)    # [[1, 2], [3, 4]]print(copied)  # [[1, 2, 99], [3, 4]]

def collect(item, bucket=None):    if bucket is None:        bucket = []    bucket.append(item)    return bucket

users = [    {"name": "Ada", "age": 36},    {"name": "Guido", "age": 70},    {"name": "Carol", "age": 36},]users_by_age = sorted(users, key=lambda user: (user["age"], user["name"]))

ranked = sorted(users, key=lambda user: (-user["age"], user["name"]))

records.sort(key=lambda r: r["name"])records.sort(key=lambda r: r["score"], reverse=True)

clean = [x for x in raw_data if x is not None]