Python----基础之数据类型（数字,字符串,列表）

什么是基本数据类型？

我们人类可以很容易的分清数字与字符的区别，但是计算机并不能呀，计算机虽然很强大，但从某种角度上看又很傻，除非你明确的告诉它，1是数字，“汉”是文字，否则它是分不清1和‘汉’的区别的，因此，在每个编程语言里都会有一个叫数据类型的东东，其实就是对常用的各种数据类型进行了明确的划分，你想让计算机进行数值运算，你就传数字给它，你想让他处理文字，就传字符串类型给他。

数字:

int

在32位机器上，整数的位数为32位，取值范围为-2**31～2**31-1，即-2147483648～2147483647

在64位系统上，整数的位数为64位，取值范围为-2**63～2**63-1，即-9223372036854775808～9223372036854775807

long

跟C语言不同，Python的长整数没有指定位宽，即：Python没有限制长整数数值的大小，但实际上由于机器内存有限，我们使用的长整数数值不可能无限大。

注意，自从Python2.2起，如果整数发生溢出，Python会自动将整数数据转换为长整数，所以如今在长整数数据后面不加字母L也不会导致严重后果了。

>>> a= 2**64
>>> type(a)  #type()是查看数据类型的方法
<type 'long'>
>>> b = 2**60
>>> type(b)
<type 'int'>

注意：在python3里不再有long类型，全部都是int

整型：

Python中的整数属于int类型，默认用十进制表示，此外也支持二进制，八进制,十六进制表示方式。

进制转换：

尽管计算机只认识二进制，但是为了迎合我们的习惯，python中的数字默认还是十进制。还提供了一些方法来帮助我们做转换。比如是十进制转换为二进制使用bin方法，在转换结果前面还会加上‘0b’表示是一个二进制数。

既然十进制可以转换为二进制，那么其实使用同样的原理也可以转换为其他进制，python也为我们提供了十进制转换成八进制和十六进制的方法，分别是oct和hex。八进制前面以‘0o’标示，十六进制以‘0x’标示。

>>> bin(10)  # bin方法是十进制转换二进制，‘0b’标示为二进制
'0b1010'
>>> oct(10)  # oct方法是十进制转换为八进制，‘0o’标示为八进制
'0o12'
>>> hex(10)  # hex方法是十进制转换为十六进制‘0x’标示为十六进制
'0xa'

取余运算（%）

>>> 7 % 5  
2
>>> 5 % 2
1
>>> 16 % 4
0

算术运算(+  -  *  /  //  divmod  **)

>>> 2+3
5
>>> 2-3
-1
>>> 2*3
6
>>> 3/2
1.5
>>> 3//2
1
>>> divmod(16,3)
(5, 1)
>>> 2**3
8

浮点型：

浮点数是属于有理数中某特定子集的数的数字表示，在计算机中用以近似表示任意某个实数。具体的说，这个实数由一个整数或定点数（即尾数）乘以某个基数（计算机中通常是2）的整数次幂得到，这种表示方法类似于基数为10的科学计数法。

为什么要叫做float浮点型?

在运算中，整数与浮点数运算的结果也是一个浮点数。

浮点数也就是小数，之所以称为浮点数，是因为按照科学记数法表示时，
一个浮点数的小数点位置是可变的，比如，
1.23*109和12.3*108是相等的。
浮点数可以用数学写法，如1.23，3.14，-9.01，等等。但是对于很大或很小的浮点数，就必须用科学计数法表示，把10用e替代：
1.23*109就是1.23e9，或者12.3e8，0.000012可以写成1.2e-5，等等。
整数和浮点数在计算机内部存储的方式是不同的，整数运算永远是精确的而浮点数运算则可能会有四舍五入的误差。

关于小数不精准问题

 Python默认的是17位精度,也就是小数点后16位，尽管有16位，但是这个精确度却是越往后越不准的。 首先，这个问题不是只存在在python中，其他语言也有同样的问题 其次，小数不精准是因为在转换成二进制的过程中会出现无限循环的情况，在约省的时候就会出现偏差。 

这里有一个问题，就是当我们的计算需要使用更高的精度（超过16位小数）的时候该怎么做呢？

#借助decimal模块的“getcontext“和“Decimal“ 方法
>>> a = 3.141592653513651054608317828332
>>> a
3.141592653513651
>>> from decimal import *
>>> getcontext()
Context(prec=50, rounding=ROUND_HALF_EVEN, Emin=-999999, Emax=999999, capitals=1, clamp=0, flags=[FloatOperation], traps=[InvalidOperation, DivisionByZero, Overflow])
>>> getcontext().prec = 50
>>> a = Decimal(1)／Decimal(3)#注，在分数计算中结果正确，如果直接定义超长精度小数会不准确
>>> a
Decimal('0.33333333333333333333333333333333333333333333333333')

>>> a = '3.141592653513651054608317828332'
>>> Decimal(a)
Decimal('3.141592653513651054608317828332')

字符串：

在python中，加了引号的都被认为是字符串！

>>> str = 'test1'
>>> str
'test1'
>>> print(type(str))
<class 'str'>
>>> str1 = '123'
>>> str1
'123'
>>> print(type(str1))
<class 'str'>
>>> str2 = "test3"
>>> str2
'test3'
>>> print(type(str2))
<class 'str'>

单双引号没有任何区别，只有在下面这种情况需要单双引号的配合：

>>> test = "I'm 18 years old"
>>> test
"I'm 18 years old"

在字符串中有单引号的时候，字符串外边要用双引号。

多引号的作用，就是多行字符串必须用字符串

msg = """
    1.打印第一行
    2.打印第二行
    3.打印第三行
"""
print(msg)

字符串拼接

>>> name = 'ike'
>>> age = '22'
>>> name + age
'ike 22'
>>> name * 5
'ikeikeikeikeike'

字符串之间可以相加，字符串可以乘法运算。

注意！字符串之间拼接，必须类型都是字符串，如果不一致会报TypeError错误

字符串的定义与创建

字符串是一个有序的字符的集合，用于存储和表示基本的文本信息

hello = "hello! everyone"'

字符串的特性与常用操作

特性:

1.按照从左到右的顺序定义字符集合，下标从0开始顺序访问，有序:

补充：

1.字符串的单引号和双引号都无法取消特殊字符的含义，如果想让引号内所有字符均取消特殊意义，在引号前面加r，如name＝r'l hf'

2.unicode字符串与r连用必需在r前面，如name＝ur'l hf'

常用操作:

# 索引取值
>>> we = 'happy'
>>> we[0]  
'h'
>>> we[-1]
'y'
>>>
>>>
# 使用index方法取索引的指
>>> we.index('y')
4

# 使用find方法查询
>>> we.index('y')
4
>>> we.find('a')
1
>>> we.find('y')
4
>>> we.find('w')
-1

# 去除空白
>>> we = '   happy   '
>>> we
'   happy   '
>>> we.strip()
'happy'
>>> we
'   happy   '
>>> we.rstrip()
'   happy'
>>> we.lstrip()
'happy   '
>>>

# len方法查长度
>>> we = 'happy'
>>> len(we)
5

# replace方法替换
>>> we = 'happy'
>>> we
'happy'
>>> we.replace('h', 'H')
'Happy'
>>> we1 = 'happy haha'
>>> we1.replace('h', 'H')
'Happy HaHa'

# 切片用法
>>> we = 'abcdefghigklmn'
>>> we[0:6]  # 从第一个到第六个
'abcdef'
>>> we[5:8]  # 从第6个到第八个
'fgh'
>>> we[:9]  # 从第一个到第9个
'abcdefghi'
>>> we[4:]  # 从第5个到最后
'efghigklmn'
>>> we[:]  # 从第一个到最后
'abcdefghigklmn'
>>> we[0:8:2]  # 从第一个到第8个，中间跳一个
'aceg'
>>> we[::2]  # 从第一个到最后一个，中间跳一个
'acegikm'
>>> we[::-1]  # 从第一个到最后一个，倒着排
'nmlkgihgfedcba 

字符串的工厂函数

class str(object):
    """
    str(object='') -> str
    str(bytes_or_buffer[, encoding[, errors]]) -> str

    Create a new string object from the given object. If encoding or
    errors is specified, then the object must expose a data buffer
    that will be decoded using the given encoding and error handler.
    Otherwise, returns the result of object.__str__() (if defined)
    or repr(object).
    encoding defaults to sys.getdefaultencoding().
    errors defaults to 'strict'.
    """
    def capitalize(self): # real signature unknown; restored from __doc__
        """
        首字母变大写
        S.capitalize() -> str

        Return a capitalized version of S, i.e. make the first character
        have upper case and the rest lower case.
        """
        return ""

    def casefold(self): # real signature unknown; restored from __doc__
        """
        S.casefold() -> str

        Return a version of S suitable for caseless comparisons.
        """
        return ""

    def center(self, width, fillchar=None): # real signature unknown; restored from __doc__
        """
        原来字符居中，不够用空格补全
        S.center(width[, fillchar]) -> str

        Return S centered in a string of length width. Padding is
        done using the specified fill character (default is a space)
        """
        return ""

    def count(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
        """
         从一个范围内的统计某str出现次数
        S.count(sub[, start[, end]]) -> int

        Return the number of non-overlapping occurrences of substring sub in
        string S[start:end].  Optional arguments start and end are
        interpreted as in slice notation.
        """
        return 0

    def encode(self, encoding='utf-8', errors='strict'): # real signature unknown; restored from __doc__
        """
        encode(encoding='utf-8',errors='strict')
        以encoding指定编码格式编码，如果出错默认报一个ValueError，除非errors指定的是
        ignore或replace

        S.encode(encoding='utf-8', errors='strict') -> bytes

        Encode S using the codec registered for encoding. Default encoding
        is 'utf-8'. errors may be given to set a different error
        handling scheme. Default is 'strict' meaning that encoding errors raise
        a UnicodeEncodeError. Other possible values are 'ignore', 'replace' and
        'xmlcharrefreplace' as well as any other name registered with
        codecs.register_error that can handle UnicodeEncodeErrors.
        """
        return b""

    def endswith(self, suffix, start=None, end=None): # real signature unknown; restored from __doc__
        """
        S.endswith(suffix[, start[, end]]) -> bool

        Return True if S ends with the specified suffix, False otherwise.
        With optional start, test S beginning at that position.
        With optional end, stop comparing S at that position.
        suffix can also be a tuple of strings to try.
        """
        return False

    def expandtabs(self, tabsize=8): # real signature unknown; restored from __doc__
        """
        将字符串中包含的	转换成tabsize个空格
        S.expandtabs(tabsize=8) -> str

        Return a copy of S where all tab characters are expanded using spaces.
        If tabsize is not given, a tab size of 8 characters is assumed.
        """
        return ""

    def find(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
        """
        S.find(sub[, start[, end]]) -> int

        Return the lowest index in S where substring sub is found,
        such that sub is contained within S[start:end].  Optional
        arguments start and end are interpreted as in slice notation.

        Return -1 on failure.
        """
        return 0

    def format(self, *args, **kwargs): # known special case of str.format
        """
        格式化输出
        三种形式：
        形式一.
        >>> print('{0}{1}{0}'.format('a','b'))
        aba

        形式二：（必须一一对应）
        >>> print('{}{}{}'.format('a','b'))
        Traceback (most recent call last):
          File "<input>", line 1, in <module>
        IndexError: tuple index out of range
        >>> print('{}{}'.format('a','b'))
        ab

        形式三：
        >>> print('{name} {age}'.format(age=12,name='lhf'))
        lhf 12

        S.format(*args, **kwargs) -> str

        Return a formatted version of S, using substitutions from args and kwargs.
        The substitutions are identified by braces ('{' and '}').
        """
        pass

    def format_map(self, mapping): # real signature unknown; restored from __doc__
        """
        与format区别
        '{name}'.format(**dict(name='alex'))
        '{name}'.format_map(dict(name='alex'))

        S.format_map(mapping) -> str

        Return a formatted version of S, using substitutions from mapping.
        The substitutions are identified by braces ('{' and '}').
        """
        return ""

    def index(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
        """
        S.index(sub[, start[, end]]) -> int

        Like S.find() but raise ValueError when the substring is not found.
        """
        return 0

    def isalnum(self): # real signature unknown; restored from __doc__
        """
        至少一个字符，且都是字母或数字才返回True

        S.isalnum() -> bool

        Return True if all characters in S are alphanumeric
        and there is at least one character in S, False otherwise.
        """
        return False

    def isalpha(self): # real signature unknown; restored from __doc__
        """
        至少一个字符，且都是字母才返回True
        S.isalpha() -> bool

        Return True if all characters in S are alphabetic
        and there is at least one character in S, False otherwise.
        """
        return False

    def isdecimal(self): # real signature unknown; restored from __doc__
        """
        S.isdecimal() -> bool

        Return True if there are only decimal characters in S,
        False otherwise.
        """
        return False

    def isdigit(self): # real signature unknown; restored from __doc__
        """
        S.isdigit() -> bool

        Return True if all characters in S are digits
        and there is at least one character in S, False otherwise.
        """
        return False

    def isidentifier(self): # real signature unknown; restored from __doc__
        """
        字符串为关键字返回True

        S.isidentifier() -> bool

        Return True if S is a valid identifier according
        to the language definition.

        Use keyword.iskeyword() to test for reserved identifiers
        such as "def" and "class".
        """
        return False

    def islower(self): # real signature unknown; restored from __doc__
        """
        至少一个字符，且都是小写字母才返回True
        S.islower() -> bool

        Return True if all cased characters in S are lowercase and there is
        at least one cased character in S, False otherwise.
        """
        return False

    def isnumeric(self): # real signature unknown; restored from __doc__
        """
        S.isnumeric() -> bool

        Return True if there are only numeric characters in S,
        False otherwise.
        """
        return False

    def isprintable(self): # real signature unknown; restored from __doc__
        """
        S.isprintable() -> bool

        Return True if all characters in S are considered
        printable in repr() or S is empty, False otherwise.
        """
        return False

    def isspace(self): # real signature unknown; restored from __doc__
        """
        至少一个字符，且都是空格才返回True
        S.isspace() -> bool

        Return True if all characters in S are whitespace
        and there is at least one character in S, False otherwise.
        """
        return False

    def istitle(self): # real signature unknown; restored from __doc__
        """
        >>> a='Hello'
        >>> a.istitle()
        True
        >>> a='HellP'
        >>> a.istitle()
        False

        S.istitle() -> bool

        Return True if S is a titlecased string and there is at least one
        character in S, i.e. upper- and titlecase characters may only
        follow uncased characters and lowercase characters only cased ones.
        Return False otherwise.
        """
        return False

    def isupper(self): # real signature unknown; restored from __doc__
        """
        S.isupper() -> bool

        Return True if all cased characters in S are uppercase and there is
        at least one cased character in S, False otherwise.
        """
        return False

    def join(self, iterable): # real signature unknown; restored from __doc__
        """
        #对序列进行操作（分别使用' '与':'作为分隔符）
        >>> seq1 = ['hello','good','boy','doiido']
        >>> print ' '.join(seq1)
        hello good boy doiido
        >>> print ':'.join(seq1)
        hello:good:boy:doiido


        #对字符串进行操作

        >>> seq2 = "hello good boy doiido"
        >>> print ':'.join(seq2)
        h:e:l:l:o: :g:o:o:d: :b:o:y: :d:o:i:i:d:o


        #对元组进行操作

        >>> seq3 = ('hello','good','boy','doiido')
        >>> print ':'.join(seq3)
        hello:good:boy:doiido


        #对字典进行操作

        >>> seq4 = {'hello':1,'good':2,'boy':3,'doiido':4}
        >>> print ':'.join(seq4)
        boy:good:doiido:hello


        #合并目录

        >>> import os
        >>> os.path.join('/hello/','good/boy/','doiido')
        '/hello/good/boy/doiido'


        S.join(iterable) -> str

        Return a string which is the concatenation of the strings in the
        iterable.  The separator between elements is S.
        """
        return ""

    def ljust(self, width, fillchar=None): # real signature unknown; restored from __doc__
        """
        S.ljust(width[, fillchar]) -> str

        Return S left-justified in a Unicode string of length width. Padding is
        done using the specified fill character (default is a space).
        """
        return ""

    def lower(self): # real signature unknown; restored from __doc__
        """
        S.lower() -> str

        Return a copy of the string S converted to lowercase.
        """
        return ""

    def lstrip(self, chars=None): # real signature unknown; restored from __doc__
        """
        S.lstrip([chars]) -> str

        Return a copy of the string S with leading whitespace removed.
        If chars is given and not None, remove characters in chars instead.
        """
        return ""

    def maketrans(self, *args, **kwargs): # real signature unknown
        """
        Return a translation table usable for str.translate().

        If there is only one argument, it must be a dictionary mapping Unicode
        ordinals (integers) or characters to Unicode ordinals, strings or None.
        Character keys will be then converted to ordinals.
        If there are two arguments, they must be strings of equal length, and
        in the resulting dictionary, each character in x will be mapped to the
        character at the same position in y. If there is a third argument, it
        must be a string, whose characters will be mapped to None in the result.
        """
        pass

    def partition(self, sep): # real signature unknown; restored from __doc__
        """
        以sep为分割，将S分成head,sep,tail三部分

        S.partition(sep) -> (head, sep, tail)

        Search for the separator sep in S, and return the part before it,
        the separator itself, and the part after it.  If the separator is not
        found, return S and two empty strings.
        """
        pass

    def replace(self, old, new, count=None): # real signature unknown; restored from __doc__
        """
        S.replace(old, new[, count]) -> str

        Return a copy of S with all occurrences of substring
        old replaced by new.  If the optional argument count is
        given, only the first count occurrences are replaced.
        """
        return ""

    def rfind(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
        """
        S.rfind(sub[, start[, end]]) -> int

        Return the highest index in S where substring sub is found,
        such that sub is contained within S[start:end].  Optional
        arguments start and end are interpreted as in slice notation.

        Return -1 on failure.
        """
        return 0

    def rindex(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
        """
        S.rindex(sub[, start[, end]]) -> int

        Like S.rfind() but raise ValueError when the substring is not found.
        """
        return 0

    def rjust(self, width, fillchar=None): # real signature unknown; restored from __doc__
        """
        S.rjust(width[, fillchar]) -> str

        Return S right-justified in a string of length width. Padding is
        done using the specified fill character (default is a space).
        """
        return ""

    def rpartition(self, sep): # real signature unknown; restored from __doc__
        """
        S.rpartition(sep) -> (head, sep, tail)

        Search for the separator sep in S, starting at the end of S, and return
        the part before it, the separator itself, and the part after it.  If the
        separator is not found, return two empty strings and S.
        """
        pass

    def rsplit(self, sep=None, maxsplit=-1): # real signature unknown; restored from __doc__
        """
        S.rsplit(sep=None, maxsplit=-1) -> list of strings

        Return a list of the words in S, using sep as the
        delimiter string, starting at the end of the string and
        working to the front.  If maxsplit is given, at most maxsplit
        splits are done. If sep is not specified, any whitespace string
        is a separator.
        """
        return []

    def rstrip(self, chars=None): # real signature unknown; restored from __doc__
        """
        S.rstrip([chars]) -> str

        Return a copy of the string S with trailing whitespace removed.
        If chars is given and not None, remove characters in chars instead.
        """
        return ""

    def split(self, sep=None, maxsplit=-1): # real signature unknown; restored from __doc__
        """
        以sep为分割，将S切分成列表，与partition的区别在于切分结果不包含sep，
        如果一个字符串中包含多个sep那么maxsplit为最多切分成几部分
        >>> a='a,b c
d	e'
        >>> a.split()
        ['a,b', 'c', 'd', 'e']
        S.split(sep=None, maxsplit=-1) -> list of strings

        Return a list of the words in S, using sep as the
        delimiter string.  If maxsplit is given, at most maxsplit
        splits are done. If sep is not specified or is None, any
        whitespace string is a separator and empty strings are
        removed from the result.
        """
        return []

    def splitlines(self, keepends=None): # real signature unknown; restored from __doc__
        """
        Python splitlines() 按照行('
', '
', 
')分隔，
        返回一个包含各行作为元素的列表，如果参数 keepends 为 False，不包含换行符，如        果为 True，则保留换行符。
        >>> x
        'adsfasdf
sadf
asdf
adf'
        >>> x.splitlines()
        ['adsfasdf', 'sadf', 'asdf', 'adf']
        >>> x.splitlines(True)
        ['adsfasdf
', 'sadf
', 'asdf
', 'adf']

        S.splitlines([keepends]) -> list of strings

        Return a list of the lines in S, breaking at line boundaries.
        Line breaks are not included in the resulting list unless keepends
        is given and true.
        """
        return []

    def startswith(self, prefix, start=None, end=None): # real signature unknown; restored from __doc__
        """
        S.startswith(prefix[, start[, end]]) -> bool

        Return True if S starts with the specified prefix, False otherwise.
        With optional start, test S beginning at that position.
        With optional end, stop comparing S at that position.
        prefix can also be a tuple of strings to try.
        """
        return False

    def strip(self, chars=None): # real signature unknown; restored from __doc__
        """
        S.strip([chars]) -> str

        Return a copy of the string S with leading and trailing
        whitespace removed.
        If chars is given and not None, remove characters in chars instead.
        """
        return ""

    def swapcase(self): # real signature unknown; restored from __doc__
        """
        大小写反转
        S.swapcase() -> str

        Return a copy of S with uppercase characters converted to lowercase
        and vice versa.
        """
        return ""

    def title(self): # real signature unknown; restored from __doc__
        """
        S.title() -> str

        Return a titlecased version of S, i.e. words start with title case
        characters, all remaining cased characters have lower case.
        """
        return ""

    def translate(self, table): # real signature unknown; restored from __doc__
        """
        table=str.maketrans('alex','big SB')

        a='hello abc'
        print(a.translate(table))

        S.translate(table) -> str

        Return a copy of the string S in which each character has been mapped
        through the given translation table. The table must implement
        lookup/indexing via __getitem__, for instance a dictionary or list,
        mapping Unicode ordinals to Unicode ordinals, strings, or None. If
        this operation raises LookupError, the character is left untouched.
        Characters mapped to None are deleted.
        """
        return ""

    def upper(self): # real signature unknown; restored from __doc__
        """
        S.upper() -> str

        Return a copy of S converted to uppercase.
        """
        return ""

    def zfill(self, width): # real signature unknown; restored from __doc__
        """
        原来字符右对齐，不够用0补齐

        S.zfill(width) -> str

        Pad a numeric string S with zeros on the left, to fill a field
        of the specified width. The string S is never truncated.
        """
        return ""

     ...略...

列表：

列表的定义和创建

定义：[]内以逗号分隔，按照索引，存放各种数据类型，每个位置代表一个元素

列表的创建：

>>> list_test = ['ike', 'jack', 'deny']
>>> list_test
['ike', 'jack', 'deny']
>>> list_test = list('ike')
>>> list_test
['i', 'k', 'e']
>>> list_test = list(['王大', '李五', '赵六'])
>>> list_test
['王大', '李五', '赵六']

列表的特点和常用操作

特性：

1.可以存放多个指

2.按照从左往右的顺序定义列表元素，下标从0开始顺序访问，有序：

3.可以修改指定索引的值，可变

常用操作：

# 索引取值
>>> we = ['test1', 'test2', 'test3']
>>> we[0]
'test1'
>>> we[2]
'test3'
>>> we[1]
'test2'
>>> we[-1]
'test3'
>>> we[-2]
'test2'

# 切片用法
>>> we
['test1', 'test2', 'test3', 'test4']
>>> we.append('test5')
>>> we
['test1', 'test2', 'test3', 'test4', 'test5']
>>> we[0:3]
['test1', 'test2', 'test3']
>>> we[2:10]
['test3', 'test4', 'test5']
>>> we[:4]
['test1', 'test2', 'test3', 'test4']
>>> we[2:5]
['test3', 'test4', 'test5']
>>> we[:]
['test1', 'test2', 'test3', 'test4', 'test5']
>>> we[::2]
['test1', 'test3', 'test5']
>>> we[::-1]
['test5', 'test4', 'test3', 'test2', 'test1']

# 追加
>>> we.append('test6')
>>> we
['test1', 'test2', 'test3', 'test4', 'test5', 'test6']
>>> we.append('test7')
>>> we
['test1', 'test2', 'test3', 'test4', 'test5', 'test6', 'test7']

# 删除
>>> we.pop()
'test7'
>>> we
['test1', 'test2', 'test3', 'test4', 'test5', 'test6']
>>> we.remove('test4')
>>> we
['test1', 'test2', 'test3', 'test5', 'test6']
>>> we.pop(2)
'test3'
>>> we
['test1', 'test2', 'test5', 'test6']

# 长度
>>> len(we)
4

# 包含
>>> we
['test1', 'test2', 'test5', 'test6']
>>> 'test1' in we
True
>>> 'test100' in we
False

# 遍历类表中的值
>>> we
['test1', 'test2', 'test5', 'test6']
>>> for i in we:
...     print(i)
...
test1
test2
test5
test6

列表与字符串——split和join

# 分割
>>> we = 'hello everyone'
>>> we.split(' ')
['hello', 'everyone']
>>> we = 'hello,everyone'
>>> we.split(',')
['hello', 'everyone']

# 连接
>>> we = ['he', 'llo']
>>> ''.join(we)
'hello'
>>> '@'.join(we)
'he@llo'

布尔型：

布尔型数据，就是一个真(True)，一个假(False)，用于逻辑判断。举例说明：

>>> 3 > 5  # 3大于5不成立，显示假(False)
False
>>> 3 <5  # 3小于5成绩,显示真(True)
True

计算机用这种类型判断不同的事件了.比如:

a = 2
b = 5
if a > b:
    print('这是错的')
else:
    print('应该是小于')

range的用法

思考:现在我们创建一个从1-100的列表,我们该怎么创建?

1.从1写到100  # 纯手工操作,耗时费力,及容易出错

2.for循环取1-100  # 效率比较快,但还不是最简单

3.range方法  # 简单,高效

>>> list(range(100))
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28,
29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55,
 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82
, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99]
>>> list(range(1,100))
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56
, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 8
3, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99]
>>> list(range(10))
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> list(range(0,100,2))
[0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54,
 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98]

总结：本文介绍初次认识数字，字符串，列表，布尔类型和常用的方法及布尔类型的基本逻辑判断。