{"id":653,"date":"2026-03-08T10:11:00","date_gmt":"2026-03-08T02:11:00","guid":{"rendered":"https:\/\/mitongxue.cn\/?p=653"},"modified":"2026-07-14T13:25:34","modified_gmt":"2026-07-14T05:25:34","slug":"python-%e4%bd%9c%e7%94%a8%e5%9f%9f%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a1%b9","status":"publish","type":"post","link":"https:\/\/mitongxue.cn\/index.php\/2026\/03\/08\/python-%e4%bd%9c%e7%94%a8%e5%9f%9f%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a1%b9\/","title":{"rendered":"python \u4f5c\u7528\u57df\u6ce8\u610f\u4e8b\u9879"},"content":{"rendered":"\n

\u5728\u51fd\u6570\u5185\u4fee\u6539\u5168\u5c40\u53d8\u91cf<\/h3>\n\n\n\n

\u76f4\u63a5\u8d4b\u503c\u4f1a\u521b\u5efa\u5c40\u90e8\u53d8\u91cf\uff0c\u800c\u975e\u4fee\u6539\u5168\u5c40\u53d8\u91cf\uff1a<\/p>\n\n\n\n

count = 0
\u200b
def wrong_increment():
    count += 1        # UnboundLocalError\uff01
\u200b
# wrong_increment()<\/code><\/pre>\n\n\n\n
\u4f7f\u7528 global<\/code> \u5173\u952e\u5b57\u58f0\u660e\uff1a<\/p>\n\n\n\n
count = 0
\u200b
def increment():
    global count      # \u58f0\u660e\u4f7f\u7528\u5168\u5c40\u53d8\u91cf
    count += 1
    print(count)
\u200b
increment()  # 1
increment()  # 2
print(count) # 2<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u95ed\u5305\u4f5c\u7528\u57df\uff08Enclosing\uff09<\/h2>\n\n\n\n
\u5d4c\u5957\u51fd\u6570\u4e2d\uff0c\u5185\u5c42\u51fd\u6570\u53ef\u4ee5\u8bbf\u95ee\u5916\u5c42\u51fd\u6570\u7684\u53d8\u91cf\uff1a\u53ef\u4ee5\u8bbf\u95ee\uff0c\u4f46\u662f\u4e0d\u80fd\u4fee\u6539\u5916\u5c42\u7684<\/p>\n\n\n\n
def outer():
    x = \"outer\"       # \u5916\u5c42\u51fd\u6570\u7684\u5c40\u90e8\u53d8\u91cf
    
    def inner():
        print(x)      # \u8bbf\u95ee\u5916\u5c42\u53d8\u91cf
    
    inner()
\u200b
outer()  # outer<\/code><\/pre>\n\n\n\n
\u62a5\u9519<\/h3>\n\n\n\n
def outer():
    x = \"outer\"       # \u5916\u5c42\u51fd\u6570\u7684\u5c40\u90e8\u53d8\u91cf
    
    def inner():
        x=x+\"inner\"
        print(x)      # \u8bbf\u95ee\u5916\u5c42\u53d8\u91cf
    
    inner()
\u200b
outer()  # outer<\/code><\/pre>\n\n\n\n
\u4f7f\u7528 nonlocal<\/code> \u5173\u952e\u5b57\uff1a<\/p>\n\n\n\n
def make_counter():
    count = 0
    
    def increment():
        nonlocal count   # \u58f0\u660e\u4f7f\u7528\u5916\u5c42\u53d8\u91cf
        count += 1
        return count
    
    return increment
\u200b
counter = make_counter()
print(counter())  # 1
print(counter())  # 2
print(counter())  # 3<\/code><\/pre>\n\n\n\n
nonlocal<\/code> vs global<\/code>\uff1a<\/strong><\/p>\n\n\n\n
\u5173\u952e\u5b57 \u4f5c\u7528 global<\/code> \u58f0\u660e\u53d8\u91cf\u6765\u81ea\u5168\u5c40<\/strong>\u4f5c\u7528\u57df nonlocal<\/code> \u58f0\u660e\u53d8\u91cf\u6765\u81ea\u5916\u5c42\u51fd\u6570<\/strong>\u4f5c\u7528\u57df<\/p>\n\n\n\n
\u5e38\u89c1\u9519\u8bef<\/h2>\n\n\n\n
\u9519\u8bef 1\uff1a\u5728\u51fd\u6570\u5185\u540c\u65f6\u8bfb\u5199\u5168\u5c40\u53d8\u91cf<\/h3>\n\n\n\n
x = 10
\u200b
def demo():
    print(x)      # \u5148\u8bfb
    x = 20        # \u518d\u5199 \u2192 \u7f16\u8bd1\u671f\u5c31\u5224\u5b9a x \u662f\u5c40\u90e8\u53d8\u91cf\uff01
\u200b
# demo()  # UnboundLocalError<\/code><\/pre>\n\n\n\n
\u539f\u56e0\uff1a<\/strong> Python \u5728\u7f16\u8bd1\u51fd\u6570\u65f6\u5c31\u786e\u5b9a\u4e86\u53d8\u91cf\u4f5c\u7528\u57df\uff0c\u4e00\u65e6\u51fd\u6570\u5185\u6709\u8d4b\u503c\u8bed\u53e5\uff0c\u8be5\u53d8\u91cf\u5c31\u88ab\u89c6\u4e3a\u5c40\u90e8\u53d8\u91cf\u3002<\/p>\n\n\n\n
\u4fee\u6b63\uff1a<\/strong><\/p>\n\n\n\n
x = 10
\u200b
def demo():
    global x
    print(x)
    x = 20
\u200b
demo()  # 10
print(x)  # 20<\/code><\/pre>\n\n\n\n
\u9519\u8bef 2\uff1a\u9ed8\u8ba4\u53c2\u6570\u7684\u9677\u9631<\/h3>\n\n\n\n
def add_item(item, items=[]):
    items.append(item)
    return items
\u200b
print(add_item(1))  # [1]
print(add_item(2))  # [1, 2] \u2014\u2014 \u610f\u5916\uff01\u5217\u8868\u88ab\u5171\u4eab\u4e86<\/code><\/pre>\n\n\n\n
\u9ed8\u8ba4\u53c2\u6570\u5728\u51fd\u6570\u5b9a\u4e49\u65f6\u6c42\u503c\uff0c\u53ea\u521b\u5efa\u4e00\u6b21\u3002<\/p>\n\n\n\n
\u4fee\u6b63\uff1a<\/strong><\/p>\n\n\n\n
def add_item(item, items=None):
    if items is None:
        items = []
    items.append(item)
    return items<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u95ed\u5305\u8ba1\u6570\u5668<\/h3>\n\n\n\n
\u5b9e\u73b0\u4e00\u4e2a\u51fd\u6570 make_multiplier(n)<\/code>\uff0c\u8fd4\u56de\u4e00\u4e2a\u51fd\u6570\u3002\u8fd4\u56de\u7684\u51fd\u6570\u63a5\u6536\u4e00\u4e2a\u53c2\u6570 x<\/code>\uff0c\u8fd4\u56de n * x<\/code>\u3002<\/p>\n\n\n\n
\u8981\u6c42\u4f7f\u7528\u95ed\u5305\u5b9e\u73b0\uff0c\u4e0d\u8981\u4f7f\u7528 global<\/code>\u3002<\/p>\n\n\n\n
def make_multiplier(x):
    def multiplier(n):
        return x * n
    return multiplier
\u200b
triple = make_multiplier(3)
print(triple(5))   # 15
print(triple(10))  # 30
\u200b
double = make_multiplier(2)
print(double(7))   # 14<\/code><\/pre>\n\n\n\n
\u5b9e\u73b0\u4e00\u4e2a\u51fd\u6570 create_account(initial_balance)<\/code>\uff0c\u8fd4\u56de\u4e24\u4e2a\u5b57\u5178\uff1a<\/h3>\n\n\n\n