from xml.etree import ElementTree as ET

# 打开文件，读取XML内容
str_xml = open('xo.xml', 'r').read()
print(str_xml, type(str_xml))
# 将字符串解析成xml特殊对象，root代指xml文件的根节点
root = ET.XML(str_xml)
print(root, type(root))

------------
<data>
    <country name="Liechtenstein">
        <rank updated="yes">2</rank>
        <year>2023</year>
        <gdppc>141100</gdppc>
        <neighbor direction="E" name="Austria" />
        <neighbor direction="W" name="Switzerland" />
    </country>
    <country name="Singapore">
        <rank updated="yes">5</rank>
        <year>2026</year>
        <gdppc>59900</gdppc>
        <neighbor direction="N" name="Malaysia" />
    </country>
    <country name="Panama">
        <rank updated="yes">69</rank>
        <year>2026</year>
        <gdppc>13600</gdppc>
        <neighbor direction="W" name="Costa Rica" />
        <neighbor direction="E" name="Colombia" />
    </country>
</data> <class 'str'>
<Element 'data' at 0x101383cc8> <class 'xml.etree.ElementTree.Element'>

from xml.etree import ElementTree as ET

# 直接解析xml文件
tree = ET.parse("xo.xml")
print(tree, type(tree)
# 获取xml文件的根节点
root = tree.getroot()
print(root, type(root))

------------
<xml.etree.ElementTree.ElementTree object at 0x101178780> <class 'xml.etree.ElementTree.ElementTree'>
<Element 'data' at 0x101283cc8> <class 'xml.etree.ElementTree.Element'>

class Element:
    """An XML element.

    This class is the reference implementation of the Element interface.

    An element's length is its number of subelements.  That means if you
    want to check if an element is truly empty, you should check BOTH
    its length AND its text attribute.

    The element tag, attribute names, and attribute values can be either
    bytes or strings.

    *tag* is the element name.  *attrib* is an optional dictionary containing
    element attributes. *extra* are additional element attributes given as
    keyword arguments.

    Example form:
        <tag attrib>text<child/>...</tag>tail

    """

    当前节点的标签名
    tag = None
    """The element's name."""

    当前节点的属性

    attrib = None
    """Dictionary of the element's attributes."""

    当前节点的内容
    text = None
    """
    Text before first subelement. This is either a string or the value None.
    Note that if there is no text, this attribute may be either
    None or the empty string, depending on the parser.

    """

    tail = None
    """
    Text after this element's end tag, but before the next sibling element's
    start tag.  This is either a string or the value None.  Note that if there
    was no text, this attribute may be either None or an empty string,
    depending on the parser.

    """

    def __init__(self, tag, attrib={}, **extra):
        if not isinstance(attrib, dict):
            raise TypeError("attrib must be dict, not %s" % (
                attrib.__class__.__name__,))
        attrib = attrib.copy()
        attrib.update(extra)
        self.tag = tag
        self.attrib = attrib
        self._children = []

    def __repr__(self):
        return "<%s %r at %#x>" % (self.__class__.__name__, self.tag, id(self))

    def makeelement(self, tag, attrib):
        创建一个新节点
        """Create a new element with the same type.

        *tag* is a string containing the element name.
        *attrib* is a dictionary containing the element attributes.

        Do not call this method, use the SubElement factory function instead.

        """
        return self.__class__(tag, attrib)

    def copy(self):
        """Return copy of current element.

        This creates a shallow copy. Subelements will be shared with the
        original tree.

        """
        elem = self.makeelement(self.tag, self.attrib)
        elem.text = self.text
        elem.tail = self.tail
        elem[:] = self
        return elem

    def __len__(self):
        return len(self._children)

    def __bool__(self):
        warnings.warn(
            "The behavior of this method will change in future versions.  "
            "Use specific 'len(elem)' or 'elem is not None' test instead.",
            FutureWarning, stacklevel=2
            )
        return len(self._children) != 0 # emulate old behaviour, for now

    def __getitem__(self, index):
        return self._children[index]

    def __setitem__(self, index, element):
        # if isinstance(index, slice):
        #     for elt in element:
        #         assert iselement(elt)
        # else:
        #     assert iselement(element)
        self._children[index] = element

    def __delitem__(self, index):
        del self._children[index]

    def append(self, subelement):
        为当前节点追加一个子节点
        """Add *subelement* to the end of this element.

        The new element will appear in document order after the last existing
        subelement (or directly after the text, if it's the first subelement),
        but before the end tag for this element.

        """
        self._assert_is_element(subelement)
        self._children.append(subelement)

    def extend(self, elements):
        为当前节点扩展 n 个子节点
        """Append subelements from a sequence.

        *elements* is a sequence with zero or more elements.

        """
        for element in elements:
            self._assert_is_element(element)
        self._children.extend(elements)

    def insert(self, index, subelement):
        在当前节点的子节点中插入某个节点，即：为当前节点创建子节点，然后插入指定位置
        """Insert *subelement* at position *index*."""
        self._assert_is_element(subelement)
        self._children.insert(index, subelement)

    def _assert_is_element(self, e):
        # Need to refer to the actual Python implementation, not the
        # shadowing C implementation.
        if not isinstance(e, _Element_Py):
            raise TypeError('expected an Element, not %s' % type(e).__name__)

    def remove(self, subelement):
        在当前节点在子节点中删除某个节点
        """Remove matching subelement.

        Unlike the find methods, this method compares elements based on
        identity, NOT ON tag value or contents.  To remove subelements by
        other means, the easiest way is to use a list comprehension to
        select what elements to keep, and then use slice assignment to update
        the parent element.

        ValueError is raised if a matching element could not be found.

        """
        # assert iselement(element)
        self._children.remove(subelement)

    def getchildren(self):
        获取所有的子节点（废弃）
        """(Deprecated) Return all subelements.

        Elements are returned in document order.

        """
        warnings.warn(
            "This method will be removed in future versions.  "
            "Use 'list(elem)' or iteration over elem instead.",
            DeprecationWarning, stacklevel=2
            )
        return self._children

    def find(self, path, namespaces=None):
        获取第一个寻找到的子节点
        """Find first matching element by tag name or path.

        *path* is a string having either an element tag or an XPath,
        *namespaces* is an optional mapping from namespace prefix to full name.

        Return the first matching element, or None if no element was found.

        """
        return ElementPath.find(self, path, namespaces)

    def findtext(self, path, default=None, namespaces=None):
        获取第一个寻找到的子节点的内容
        """Find text for first matching element by tag name or path.

        *path* is a string having either an element tag or an XPath,
        *default* is the value to return if the element was not found,
        *namespaces* is an optional mapping from namespace prefix to full name.

        Return text content of first matching element, or default value if
        none was found.  Note that if an element is found having no text
        content, the empty string is returned.

        """
        return ElementPath.findtext(self, path, default, namespaces)

    def findall(self, path, namespaces=None):
        获取所有的子节点
        """Find all matching subelements by tag name or path.

        *path* is a string having either an element tag or an XPath,
        *namespaces* is an optional mapping from namespace prefix to full name.

        Returns list containing all matching elements in document order.

        """
        return ElementPath.findall(self, path, namespaces)

    def iterfind(self, path, namespaces=None):
        获取所有指定的节点，并创建一个迭代器（可以被for循环）
        """Find all matching subelements by tag name or path.

        *path* is a string having either an element tag or an XPath,
        *namespaces* is an optional mapping from namespace prefix to full name.

        Return an iterable yielding all matching elements in document order.

        """
        return ElementPath.iterfind(self, path, namespaces)

    def clear(self):
        清空节点
        """Reset element.

        This function removes all subelements, clears all attributes, and sets
        the text and tail attributes to None.

        """
        self.attrib.clear()
        self._children = []
        self.text = self.tail = None

    def get(self, key, default=None):
        获取当前节点的属性值
        """Get element attribute.

        Equivalent to attrib.get, but some implementations may handle this a
        bit more efficiently.  *key* is what attribute to look for, and
        *default* is what to return if the attribute was not found.

        Returns a string containing the attribute value, or the default if
        attribute was not found.

        """
        return self.attrib.get(key, default)

    def set(self, key, value):
        为当前节点设置属性值
        """Set element attribute.

        Equivalent to attrib[key] = value, but some implementations may handle
        this a bit more efficiently.  *key* is what attribute to set, and
        *value* is the attribute value to set it to.

        """
        self.attrib[key] = value

    def keys(self):
        获取当前节点的所有属性的 key

        """Get list of attribute names.

        Names are returned in an arbitrary order, just like an ordinary
        Python dict.  Equivalent to attrib.keys()

        """
        return self.attrib.keys()

    def items(self):
        获取当前节点的所有属性值，每个属性都是一个键值对
        """Get element attributes as a sequence.

        The attributes are returned in arbitrary order.  Equivalent to
        attrib.items().

        Return a list of (name, value) tuples.

        """
        return self.attrib.items()

    def iter(self, tag=None):
        在当前节点的子孙中根据节点名称寻找所有指定的节点，并返回一个迭代器（可以被for循环）。
        """Create tree iterator.

        The iterator loops over the element and all subelements in document
        order, returning all elements with a matching tag.

        If the tree structure is modified during iteration, new or removed
        elements may or may not be included.  To get a stable set, use the
        list() function on the iterator, and loop over the resulting list.

        *tag* is what tags to look for (default is to return all elements)

        Return an iterator containing all the matching elements.

        """
        if tag == "*":
            tag = None
        if tag is None or self.tag == tag:
            yield self
        for e in self._children:
            yield from e.iter(tag)

    # compatibility
    def getiterator(self, tag=None):
        # Change for a DeprecationWarning in 1.4
        warnings.warn(
            "This method will be removed in future versions.  "
            "Use 'elem.iter()' or 'list(elem.iter())' instead.",
            PendingDeprecationWarning, stacklevel=2
        )
        return list(self.iter(tag))

    def itertext(self):
        在当前节点的子孙中根据节点名称寻找所有指定的节点的内容，并返回一个迭代器（可以被for循环）。
        """Create text iterator.

        The iterator loops over the element and all subelements in document
        order, returning all inner text.

        """
        tag = self.tag
        if not isinstance(tag, str) and tag is not None:
            return
        if self.text:
            yield self.text
        for e in self:
            yield from e.itertext()
            if e.tail:
                yield e.tail

from xml.etree import ElementTree as ET
 
# 直接解析xml文件
tree = ET.parse("xo.xml")

# 获取xml文件的根节点
root = tree.getroot()

# 获取顶层标签
print(root.tag)

# 遍历xml文档的第二层
for i in root:
    # 第二层节点的标签名称和标签属性
    print(i.tag, i.attrib)
    # 遍历xml文档的第三层
    for j in i:
        print(j.tag, j.text)
        
 ------------
data
country {'name': 'Liechtenstein'}
rank 2
year 2023
gdppc 141100
neighbor None
neighbor None
country {'name': 'Singapore'}
rank 5
year 2026
gdppc 59900
neighbor None
country {'name': 'Panama'}
rank 69
year 2026
gdppc 13600
neighbor None
neighbor None

from xml.etree import ElementTree as ET

# 直接解析xml文件
tree = ET.parse("xo.xml")

# 获取xml文件的根节点
root = tree.getroot()

# 获取顶层标签
print(root.tag)

# root.iter()的参数中可以填入任意一个节点名称
for node in root.iter("gdppc"):
    # 节点的标签名称和内容
    print(node.tag, node.text)
    
------------
data
gdppc 141100
gdppc 59900
gdppc 13600

from xml.etree import ElementTree as ET

# 打开文件,将文件的内容读到内存中
str_xml = open("xo.xml", 'r').read()

# 将字符串解析成xml特殊对象,root代指xml文件的根节点
root = ET.XML(str_xml)


# 开始操作xml对象
# 打印一下顶层的标签
print(root.tag)

# 循环所有的year节点
for node in root.iter("year"):
    # 将year节点中的内容自增一
    new_year = int(node.text) + 1
    node.text = str(new_year)

    # 设置属性
    node.set("name", "polarsnow")
    node.set("age", "25")

    # 删除属性
    del node.attrib["age"]

# 保存文件
## 使用读取字符串的方式在保存之前需要先创建ElementTree对象
tree = ET.ElementTree(root)
tree.write("newxo.xml", encoding="utf-8")

from xml.etree import ElementTree as ET

# 直接解析xml文件
tree = ET.parse("xo.xml")

# 获取xml文件的根节点
root = tree.getroot()

# 开始操作xml对象
# 顶层标签
print(root.tag)

# 循环所有的year节点
for node in root.iter("year"):
    # 将year节点中的内容自增一
    new_year = int(node.text) + 1
    node.text = str(new_year)

    # 设置属性
    node.set("name", "polarsnow")
    node.set("age", "25")

    # 删除属性
    del node.attrib["age"]

# 保存文件
## 使用parse的方式直接解析xml文件，已经生成了ElementTree对象
## 可以直接调用写的方法
tree.write("newxo.xml", encoding="utf-8")

from xml.etree import ElementTree as ET

# 打开文件，读取XML内容
str_xml = open('xo.xml', 'r').read()

# 将字符串解析成xml特殊对象，root代指xml文件的根节点
root = ET.XML(str_xml)

# 开始操作xml对象
# 顶层标签
print(root.tag)

# 遍历data下的所有country节点
for country in root.findall('country'):
    # 获取每一个country节点下rank节点的内容
    rank = int(country.find('rank').text)

    if rank > 50:
        # 删除指定country节点
        root.remove(country)

# 保存文件
tree = ET.ElementTree(root)
tree.write("newxo.xml", encoding='utf-8')

from xml.etree import ElementTree as ET

# 直接解析xml文件
tree = ET.parse("xo.xml")

# 获取xml文件的根节点
root = tree.getroot()

# 开始操作xml对象
# 顶层标签
print(root.tag)

# 遍历data下的所有country节点
for country in root.findall('country'):
    # 获取每一个country节点下rank节点的内容
    rank = int(country.find('rank').text)

    if rank > 50:
        # 删除指定country节点
        root.remove(country)

# 保存文件
tree.write("newnew.xml", encoding='utf-8')

from xml.etree import ElementTree as ET

# 创建根节点
root = ET.Element("World")

# 创建二级节点
country1 = ET.Element("country", {"name": "China"})
country2 = ET.Element("country", {"name": "America"})

# 创建三级节点
city1 = ET.Element("city", {"name": "BeiJing"})
city2 = ET.Element("city", {"name": "TangShan"})

# 把创建的三级节点添加到二级节点下面
country1.append(city1)
country1.append(city2)

# 再把二级节点添加到跟节点中
root.append(country1)
root.append(country2)

# 创建ElementTree对象
tree = ET.ElementTree(root)
tree.write("xxxx.xml", encoding="utf-8", short_empty_elements=False)

from xml.etree import ElementTree as ET

# 创建根节点
root = ET.Element("World")

# 创建二级节点
country1 = root.makeelement("country", {"name": "China"})
country2 = root.makeelement("country", {"name": "America"})

# 创建三级节点
city1 = country1.makeelement("city", {"name": "BeiJing"})
city2 = country1.makeelement("city", {"name": "TangShan"})

# 把创建的三级节点添加到二级节点下面
country1.append(city1)
country1.append(city2)

# 再把二级节点添加到跟节点中
root.append(country1)
root.append(country2)

# 创建ElementTree对象
tree = ET.ElementTree(root)
tree.write("xxxx.xml", encoding="utf-8", short_empty_elements=False)

from xml.etree import ElementTree as ET

# 创建根节点
root = ET.Element("World")

# 创建二级节点
country1 = ET.SubElement(root, "country", attrib={"name": "China"})
country2 = ET.SubElement(root, "country", attrib={"name": "America"})

# 创建三级节点
city1 = ET.SubElement(country1, "city", attrib={"name": "BeiJing"})
city2 = ET.SubElement(country1, "city", attrib={"name": "TangShan"})

et = ET.ElementTree(root)  # 生成文档对象
# xml_declaration 添加xml版本信息注释
et.write("test.xml", encoding="utf-8", xml_declaration=True, short_empty_elements=False)

from xml.etree import ElementTree as ET
from xml.dom import minidom


def prettify(elem):
    """将节点转换成字符串，并添加缩进"""
    rough_string = ET.tostring(elem, 'utf-8')
    reparsed = minidom.parseString(rough_string)
    return reparsed.toprettyxml(indent="\t")
    
# 创建根节点
root = ET.Element("World")

# 创建二级节点
country1 = ET.SubElement(root, "country", attrib={"name": "China"})
country2 = ET.SubElement(root, "country", attrib={"name": "America"})

# 创建三级节点
city1 = ET.SubElement(country1, "city", attrib={"name": "BeiJing"})
city2 = ET.SubElement(country1, "city", attrib={"name": "TangShan"})

raw_str = prettify(root)

with open("xxoo.xml", 'w', encoding="utf-8") as f:
    f.write(raw_str)

import configparser

config = configparser.ConfigParser()
config.read('test.conf', encoding='utf-8')
ret = config.sections()
print(ret)

------------
['mysql', 'python']

import configparser

config = configparser.ConfigParser()
config.read('test.conf', encoding='utf-8')
ret = config.items('mysql')
print(ret)

------------
[('version', '5.7')]

import configparser

config = configparser.ConfigParser()
config.read('test.conf', encoding='utf-8')
ret = config.options('mysql')
print(ret)

------------
['version']

import configparser

config = configparser.ConfigParser()
config.read('test.conf', encoding='utf-8')
# ret = config.get('mysql', 'version')
# print(ret, type(ret))
# ret = config.getint('mysql', 'version')
# print(ret, type(ret))
ret = config.getfloat('mysql', 'version')
print(ret, type(ret))
# ret = config.getboolean('mysql', 'version')
# print(ret, type(ret))

------------
5.7 <class 'float'>

import configparser

config = configparser.ConfigParser()
config.read('test.conf', encoding='utf-8')

# 检查配置文件中有没有指定的节点
has_sec = config.has_section('mysql')
print(has_sec)

# 在配置文件中添加新的节点
config.add_section('java')
config.write(open('test.conf', 'w'))

# 在配置文件中删除已有的节点
config.remove_section('python')
config.write(open('test.conf', 'w'))

------------
True

import configparser

config = configparser.ConfigParser()
config.read('test.conf', encoding='utf-8')

# 检查配置文件中有没有指定的节点
has_opt = config.has_option('mysql', 'version')
print(has_opt)

# 在配置文件中修改节点
config.set('mysql', 'path', '/usr/local/src/mysql')
config.write(open('test.conf', 'w'))

# 删除节点下指定的键值对
config.remove_option('mysql', 'version')
config.write(open('test.conf', 'w'))

------------
True

>>> re.findall(r"python", "Pythonpythoner", re.I)
['Python', 'python']

>>> re.findall(r"^python$", "Pythonpythoner", re.I)
[]
>>> re.findall(r"^python$", "Python", re.I)
['Python']

>>> re.findall(r"python|java", "Python and java", re.I)
['Python', 'java']

>>> re.findall(r"\\", "Python\ and java", re.I)
['\\']

>>> print('\\')
\
>>> print(r'\\')
\\

>>> re.findall("\\\\", "Python\ and java", re.I)
['\\']

def match(pattern, string, flags=0):
    """Try to apply the pattern at the start of the string, returning
    a match object, or None if no match was found."""
    return _compile(pattern, flags).match(string)

# 无分组

import re

r = re.match('com', 'comwww.runcomoob')
print(r.group())
print(r.groups())
print(r.groupdict())

r = re.match('com', 'Comwww.runComoob', re.I)
print(r.group())
print(r.groups())
print(r.groupdict())

------------
com
()
{}
Com
()
{}

# 有分组
# 为何要有分组？提取匹配成功的指定内容（先匹配成功全部正则，再匹配成功的局部内容提取出来）

import re

r = re.match('c(..)', 'comwww.runcomoob')
print(r.group())
print(r.groups())
print(r.groupdict())

r = re.match('c(..)', 'Comwww.runComoob', re.I)
print(r.group())
print(r.groups())
print(r.groupdict())

------------
com
('om',)
{}
Com
('om',)
{}

def search(pattern, string, flags=0):
    """Scan through string looking for a match to the pattern, returning
    a match object, or None if no match was found."""
    return _compile(pattern, flags).search(string)

import re

r = re.search('\dcom', 'www.4comrunoob.5com')
print(r.group())
print(r.groups())
print(r.groupdict())

------------
4com
()
{}

def findall(pattern, string, flags=0):
    """Return a list of all non-overlapping matches in the string.

    If one or more capturing groups are present in the pattern, return
    a list of groups; this will be a list of tuples if the pattern
    has more than one group.

    Empty matches are included in the result."""
    return _compile(pattern, flags).findall(string)

# 无分组

import re

r = re.findall(r'\d+', '1one1two2three3four4')
print(r)


# 有分组
r = re.findall(r'\d+(..)', '1one1two2three3four4')
print(r)

------------
['1', '1', '2', '3', '4']
['on', 'tw', 'th', 'fo']

import

r = re.finditer(r'\d+', '1one1two2three3four4')
print(r)
for i in r:
    print(i.span(), i.group(), i.groupdict())
    
------------
<callable_iterator object at 0x101178748>
(0, 1) 1 {}
(4, 5) 1 {}
(8, 9) 2 {}
(14, 15) 3 {}
(19, 20) 4 {}

def sub(pattern, repl, string, count=0, flags=0):
    """Return the string obtained by replacing the leftmost
    non-overlapping occurrences of the pattern in string by the
    replacement repl.  repl can be either a string or a callable;
    if a string, backslash escapes in it are processed.  If it is
    a callable, it's passed the match object and must return
    a replacement string to be used."""
    return _compile(pattern, flags).sub(repl, string, count)

# 与分组无关
import re

r = re.sub("a\w+", "18", "hello ps bcd ps lge ps acd 25", 2)
print(r)

------------
hello ps bcd ps lge ps 18 25

def split(pattern, string, maxsplit=0, flags=0):
    """Split the source string by the occurrences of the pattern,
    returning a list containing the resulting substrings.  If
    capturing parentheses are used in pattern, then the text of all
    groups in the pattern are also returned as part of the resulting
    list.  If maxsplit is nonzero, at most maxsplit splits occur,
    and the remainder of the string is returned as the final element
    of the list."""
    return _compile(pattern, flags).split(string, maxsplit)

# 无分组

import re

origin = "hello ps bcd ps lge ps acd 25"
r = re.split("ps", "hello ps bcd ps lge ps acd 25", 1)
print(r)
r = re.split("ps", "hello ps bcd ps lge ps acd 25", 2)
print(r)
r = re.split("ps", "hello ps bcd ps lge ps acd 25", 3)
print(r)

------------
['hello ', ' bcd ps lge ps acd 25']
['hello ', ' bcd ', ' lge ps acd 25']
['hello ', ' bcd ', ' lge ', ' acd 25']

# 有分组

import re

origin = "hello ps bcd ps lge ps acd 25"
r = re.split("(ps)", "hello ps bcd ps lge ps acd 25", 1)
print(r)
r = re.split("p(s)", "hello ps bcd ps lge ps acd 25", 1)
print(r)

------------
['hello ', 'ps', ' bcd ps lge ps acd 25']
['hello ', 's', ' bcd ps lge ps acd 25']

def compile(pattern, flags=0):
    "Compile a regular expression pattern, returning a pattern object."
    return _compile(pattern, flags)

import re

p = re.compile(r'\d+(...)')
print(p.findall('123one134two256three378four469'))

------------
['one', 'two', 'thr', 'fou']

import re

# test_expression = '12+33*(11.5+22.5)*44/2+59-(2*3)+(8*5-(10/2))'


def qukuohao(s):
    """
    将表达式中所有括号中的内容计算成数值,去掉表达式中所有的括号
    :param s: 计算表达式[str]
    :return: 没有括号的计算表达式[str]
    """
    while True:
        if '(' in s:
            r = re.split(r'\(([^()]*)\)', s, 1)
            # ret = eval(r[1])
            ret = cal(r[1])
            s = r[0] + str(ret) + r[2]
        else:
            return s


def fuhao(s):
    """
    处理符号的问题
    :param s: 计算表达式
    :return: 计算表达式
    """
    ss = s.replace('+-', '-')
    sss = ss.replace('--', '+')
    return sss


def chengshufajisuan(s):
    """
    专门用来计算不带括号的计算表达式中的乘除法
    :param s: 不带括号的计算表达式
    :return: 只有加减法的计算表达式(如果不再有加减法,直接返回计算结果)
    """
    while True:
        if '*' in s or '/' in s:
            r = re.split(r'(\d+\.?\d*[*|/]-?\d+\.?\d*)', s, 1)
            ss = eval(r[1])
            s = r[0] + str(ss) + r[2]
        else:
            break
    return s


def jiajianfajisuan(s):
    """
    专门用来计算不带括号的计算表示式中的加减法
    :param s: 不带括号且只有加减法的表达式
    :return: 最终的计算结果
    """
    s = fuhao(s)
    while True:
    	# 5-9的情况；-5-9的情况都需要额外考虑
        if '+' in s or s.count('-') > 1 or (s.count('-') == 1 and not s.startswith('-')):
            r = re.split(r'(-?\d+\.?\d*[+|-]\d+\.?\d*)', s, 1)
            ss = eval(r[1])
            s = r[0]+str(ss)+r[2]
        else:
            break
    return s


def cal(s):
    """
    + - * / 混合运算
    :param s:
    :return:
    """
    if '*' in s or '/' in s:
        s = chengshufajisuan(s)
        if '+' in s or s.count('-') > 1:
            s = jiajianfajisuan(s)
            return s
        else:
            return s
    elif '+' in s or s.count('-') > 1 or (s.count('-') == 1 and not s.startswith('-')):
        s = jiajianfajisuan(s)
        return s
    else:
        return None

# print(cal(qukuohao(test_expression)))

if __name__ == '__main__':
    try:
        while True:
            e = input('输入计算表达式> ')
            if '(' in e:
                print(cal(qukuohao(e)))
            else:
                print(cal(e))
    except KeyboardInterrupt:
        print('Bye')

# commons.py
def login():
    print('登录页面!')

def logout():
    print('退出页面!')

def index():
    print('主页面')

# index.py
import commons

inp = input('url > ')

if inp == 'login':
    commons.login()
elif inp == 'logout':
    commons.logout()
elif inp == 'index':
    commons.index()
else:
    print('404')

------------
url > login
登录页面!

# index.py
import commons

def run():
    inp = input('url > ')
    if hasattr(commons, inp):
        func = getattr(commons, inp)
        func()
    else:
        print('404')

if __name__ == "__main__":
    run()
    
------------
url > logout
退出页面!

def getattr(object, name, default=None): # known special case of getattr
    """
    getattr(object, name[, default]) -> value
    
    Get a named attribute from an object; getattr(x, 'y') is equivalent to x.y.
    When a default argument is given, it is returned when the attribute doesn't
    exist; without it, an exception is raised in that case.
    """
    pass

def hasattr(*args, **kwargs): # real signature unknown
    """
    Return whether the object has an attribute with the given name.
    
    This is done by calling getattr(obj, name) and catching AttributeError.
    """
    pass

import commons

print(dir(commons))
delattr(commons, 'index')
print(dir(commons))

------------
['__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', 'index', 'login', 'logout']
['__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', 'login', 'logout']

def setattr(x, y, v): # real signature unknown; restored from __doc__
    """
    Sets the named attribute on the given object to the specified value.
    
    setattr(x, 'y', v) is equivalent to ``x.y = v''
    """
    pass

import commons

commons.index()

def newindex():
    print('new 主页面!')

setattr(commons, 'index', newindex)

commons.index()

------------
主页面
new 主页面!

# account.py
def add_user():
    print('添加用户')

def del_user():
    print('删除用户')

# commons.py
def login():
    print('登录页面!')

def logout():
    print('退出页面!')

def index():
    print('主页面')

# index.py
def run():
    inp = input('url > ')
    m, f = inp.split('/')
    obj_module = __import__(m)
    if hasattr(obj_module, f):
        func = getattr(obj_module, f)
        func()
    else:
        print('404')

if __name__ == "__main__":
    run()