Python| locals()函数

Python locals()函数返回当前本地符号表的字典。

• 符号表：它是由编译器创建的数据结构，用于存储执行程序所需的所有信息。
• 本地符号表：此符号表存储程序本地范围所需的所有信息，并且可以使用Python内置函数locals() 访问此信息。

Syntax : locals()

Parameters: This function does not takes any input parameter. 

Return Type : This returns the information stored in local symbol table.

Python locals() 方法示例

示例 1： Python locals() 在本地范围内工作

Python3

# Python program to understand about locals
# here no local variable is present
 
def demo1():
    print("Here no local variable  is present : ", locals())
 
# here local variables are present
def demo2():
    name = "Ankit"
    print("Here local variables are present : ", locals())
 
# driver code
demo1()
demo2()

输出;

Here no local variable  is present :  {}
Here local variables are present :  {'name': 'Ankit'}

示例 2：使用 locals() 更新

与 globals() 不同，此函数不能修改本地符号表的数据。下面的程序清楚地解释了它。

Python3

# Python program to understand about locals
# here no local variable is present
 
def demo1():
    print("Here no local variable  is present : ", locals())
 
# here local variables are present
def demo2():
    name = "Ankit"
    print("Here local variables are present : ", locals())
    print("Before updating name is  : ", name)
 
    # trying to change name value
    locals()['name'] = "Sri Ram"
 
    print("after updating name is : ", name)
 
# driver code
demo1()
demo2()

输出：

Here no local variable  is present :  {}
Here local variables are present :  {'name': 'Ankit'}
Before updating name is  :  Ankit
after updating name is :  Ankit

示例 3：全局环境的 locals()

在全局环境的情况下，局部符号表与全局符号表相同。

Python3

# Python program to understand about locals
 
# data using locals
print("This is using locals() : ", locals())
 
# data using globals
print("This is using globals() : ", globals())

输出：

This is using locals() :  {‘__name__’: ‘__main__’, ‘__doc__’: ‘Automatically created module for IPython interactive environment’, ‘__package__’: None, ‘__loader__’: None, ‘__spec__’: None, ‘__builtin__’: , ‘__builtins__’: , ‘_ih’: [”, ‘import multiprocessing\nfrom bs4 import BeautifulSoup\nfrom queue import Queue, Empty\nfrom concurrent.futures import ThreadPoolExecutor\nfrom urllib.parse import urljoin, urlparse\nimport requests\n\n\nclass MultiThreadedCrawler:\n\n    def __init__(self, seed_url):\n        self.seed_url = seed_url\n        self.root_url = \'{}://{}\’.format(urlparse(self.seed_url).scheme,\n                                         urlparse(self.seed_url).netloc)\n        self.pool = ThreadPoolExecutor(max_workers=5)\n        self.scraped_pages = set([])\n        self.crawl_queue = Queue()\n        self.crawl_queu

Python本地 VS 全局函数

Python中的Python globals()函数返回当前全局符号表的字典。

Syntax: globals()

Parameters: No parameters required.

Python3

# Python3 program to demonstrate global() function
 
# global variable
a = 5
 
def func():
    c = 10
    d = c + a
     
    # Calling globals()
    globals()['a'] = d
    print (d)
     
# Driver Code   
func()

输出：

15

Python中的Python locals()函数返回当前本地符号表的字典。

Python3

locals()

输出：

{‘__name__’: ‘__main__’,

 ‘__doc__’: ‘Automatically created module for IPython interactive environment’,

 ‘__package__’: None,

 ‘__loader__’: None,

 ‘__spec__’: None,

 ‘__builtin__’: ,

 ‘__builtins__’: ,

 ‘_ih’: [”,

  ‘# Python program to demonstrate the use of\n# len() method  \n\n# Length of below string is 5\nstring = “geeks” \nprint(len(string))\n\n# Length of below string is 15\nstring = “geeks for geeks” \nprint(len(string))’,

  ‘# Python program to demonstrate the use of\n# len() method  \n\n# L