Python基本数据类型(数字)

时间:2022-05-29 17:26:47
基本数据类型

一、数字

Python中的数字类型主要包括五种,分别是整型、长整型、浮点型、复数型和布尔型。

1.整型

整型(Integer)是最基本的数字类型,支持加减乘除运算。除了加减乘除,还可以用“%”进行取余操作,用“**”进行指数操作,用“//”进行整数除法操作

v = 2 + 2
print(v)     #结果为:4

2.长整型

当整型超出最大最小值的范围时,Python会自动将超出范围的整数转化为长整型(Long Integer)

3.浮点型

为了让除法12/5返回结果是2.4而不是2,我们可以使用浮点型进行计算:

v = 12.0/5.0
print(v)       #结果为:2.4

浮点型与整型的运算结果还是浮点型。浮点数还支持整数除法。在Python中,整数除法是一种特殊的除法,用“//”表示,返回的是比实际结果小的最大整数值:

v = 12.3 // -4
print(v)         #结果为:-4.0

4.复数型

复数型是表示复数的类型,定义时,Python使用字母j来表示复数的虚部:

v = 1+2j
a = v.real
b = v.imag
print(a,b)      #结果为:1.0  2.0    

5.布尔型

布尔型可以看成是一种取值为Ture和False的二值变量,分别对应逻辑上的真和假。

布尔型变量可以使用比较表达式得到:

v = 1>2
print(v)     #结果为:False

常用的比较符号包括小于“<”、大于“>”、小于或等于“<=” 、大于或等于“>=”、 不等于“!=”等。

6.运算优先级

Python中各种运算也有一定的优先顺序,优先级从高到低排序如下:

  • (),括号 
  • **,乘幂运算
  • *、/、//、%,乘、除、整数除法、取余
  • +、-,加、减

7.原地运算

 Python支持原地运算的操作,其形式如下:

v = 2.5
v += 1
print(v)     #结果为:3.5

8.数字函数

Python提供了一些简单的数学函数对数字进行处理。例如,求绝对值(abs)、四舍五入取整(round)、最大值(max)、最小值(min)等。

9.类型转换

不同类型的数字间可以进行类型转换。

  • int()函数可以将浮点型转化为整型,但只保留整数部分。
  • 整型转浮点型的函数为float()
  • 整型、浮点型转长整型的函数为long()
  • 整型、浮点型转复数型的函数为complex()

10.整型的其他表示

通常整型的表示是以十进制为基础的。在计算机科学中,还存在其他进制的表示方法,如二进制、八进制和十六进制。

Python中的二进制数字以0b开头、八进制数字以0或者0o开头、十六进制数字以0x开头

11.整型的方法

最常用的方法为int(),可将字符串转换为数字:

a = "123"
b = int(a)
print(b)     #结果为:123

整型所有方法归纳:

Python基本数据类型(数字)Python基本数据类型(数字)
  1 class int(object):
  2     """
  3     int(x=0) -> int or long
  4     int(x, base=10) -> int or long
  5     
  6     Convert a number or string to an integer, or return 0 if no arguments
  7     are given.  If x is floating point, the conversion truncates towards zero.
  8     If x is outside the integer range, the function returns a long instead.
  9     
 10     If x is not a number or if base is given, then x must be a string or
 11     Unicode object representing an integer literal in the given base.  The
 12     literal can be preceded by '+' or '-' and be surrounded by whitespace.
 13     The base defaults to 10.  Valid bases are 0 and 2-36.  Base 0 means to
 14     interpret the base from the string as an integer literal.
 15     >>> int('0b100', base=0)
 16     """
 17     def bit_length(self): 
 18         """ 返回表示该数字的时占用的最少位数 """
 19         """
 20         int.bit_length() -> int
 21         
 22         Number of bits necessary to represent self in binary.
 23         >>> bin(37)
 24         '0b100101'
 25         >>> (37).bit_length()
 26         """
 27         return 0
 28 
 29     def conjugate(self, *args, **kwargs): # real signature unknown
 30         """ 返回该复数的共轭复数 """
 31         """ Returns self, the complex conjugate of any int. """
 32         pass
 33 
 34     def __abs__(self):
 35         """ 返回绝对值 """
 36         """ x.__abs__() <==> abs(x) """
 37         pass
 38 
 39     def __add__(self, y):
 40         """ x.__add__(y) <==> x+y """
 41         pass
 42 
 43     def __and__(self, y):
 44         """ x.__and__(y) <==> x&y """
 45         pass
 46 
 47     def __cmp__(self, y): 
 48         """ 比较两个数大小 """
 49         """ x.__cmp__(y) <==> cmp(x,y) """
 50         pass
 51 
 52     def __coerce__(self, y):
 53         """ 强制生成一个元组 """ 
 54         """ x.__coerce__(y) <==> coerce(x, y) """
 55         pass
 56 
 57     def __divmod__(self, y): 
 58         """ 相除,得到商和余数组成的元组 """ 
 59         """ x.__divmod__(y) <==> divmod(x, y) """
 60         pass
 61 
 62     def __div__(self, y): 
 63         """ x.__div__(y) <==> x/y """
 64         pass
 65 
 66     def __float__(self): 
 67         """ 转换为浮点类型 """ 
 68         """ x.__float__() <==> float(x) """
 69         pass
 70 
 71     def __floordiv__(self, y): 
 72         """ x.__floordiv__(y) <==> x//y """
 73         pass
 74 
 75     def __format__(self, *args, **kwargs): # real signature unknown
 76         pass
 77 
 78     def __getattribute__(self, name): 
 79         """ x.__getattribute__('name') <==> x.name """
 80         pass
 81 
 82     def __getnewargs__(self, *args, **kwargs): # real signature unknown
 83         """ 内部调用 __new__方法或创建对象时传入参数使用 """ 
 84         pass
 85 
 86     def __hash__(self): 
 87         """如果对象object为哈希表类型,返回对象object的哈希值。哈希值为整数。在字典查找中,哈希值用于快速比较字典的键。两个数值如果相等,则哈希值也相等。"""
 88         """ x.__hash__() <==> hash(x) """
 89         pass
 90 
 91     def __hex__(self): 
 92         """ 返回当前数的 十六进制 表示 """ 
 93         """ x.__hex__() <==> hex(x) """
 94         pass
 95 
 96     def __index__(self): 
 97         """ 用于切片,数字无意义 """
 98         """ x[y:z] <==> x[y.__index__():z.__index__()] """
 99         pass
100 
101     def __init__(self, x, base=10): # known special case of int.__init__
102         """ 构造方法,执行 x = 123 或 x = int(10) 时,自动调用,暂时忽略 """ 
103         """
104         int(x=0) -> int or long
105         int(x, base=10) -> int or long
106         
107         Convert a number or string to an integer, or return 0 if no arguments
108         are given.  If x is floating point, the conversion truncates towards zero.
109         If x is outside the integer range, the function returns a long instead.
110         
111         If x is not a number or if base is given, then x must be a string or
112         Unicode object representing an integer literal in the given base.  The
113         literal can be preceded by '+' or '-' and be surrounded by whitespace.
114         The base defaults to 10.  Valid bases are 0 and 2-36.  Base 0 means to
115         interpret the base from the string as an integer literal.
116         >>> int('0b100', base=0)
117         # (copied from class doc)
118         """
119         pass
120 
121     def __int__(self): 
122         """ 转换为整数 """ 
123         """ x.__int__() <==> int(x) """
124         pass
125 
126     def __invert__(self): 
127         """ x.__invert__() <==> ~x """
128         pass
129 
130     def __long__(self): 
131         """ 转换为长整数 """ 
132         """ x.__long__() <==> long(x) """
133         pass
134 
135     def __lshift__(self, y): 
136         """ x.__lshift__(y) <==> x<<y """
137         pass
138 
139     def __mod__(self, y): 
140         """ x.__mod__(y) <==> x%y """
141         pass
142 
143     def __mul__(self, y): 
144         """ x.__mul__(y) <==> x*y """
145         pass
146 
147     def __neg__(self): 
148         """ x.__neg__() <==> -x """
149         pass
150 
151     @staticmethod # known case of __new__
152     def __new__(S, *more): 
153         """ T.__new__(S, ...) -> a new object with type S, a subtype of T """
154         pass
155 
156     def __nonzero__(self): 
157         """ x.__nonzero__() <==> x != 0 """
158         pass
159 
160     def __oct__(self): 
161         """ 返回改值的 八进制 表示 """ 
162         """ x.__oct__() <==> oct(x) """
163         pass
164 
165     def __or__(self, y): 
166         """ x.__or__(y) <==> x|y """
167         pass
168 
169     def __pos__(self): 
170         """ x.__pos__() <==> +x """
171         pass
172 
173     def __pow__(self, y, z=None): 
174         """ 幂,次方 """ 
175         """ x.__pow__(y[, z]) <==> pow(x, y[, z]) """
176         pass
177 
178     def __radd__(self, y): 
179         """ x.__radd__(y) <==> y+x """
180         pass
181 
182     def __rand__(self, y): 
183         """ x.__rand__(y) <==> y&x """
184         pass
185 
186     def __rdivmod__(self, y): 
187         """ x.__rdivmod__(y) <==> divmod(y, x) """
188         pass
189 
190     def __rdiv__(self, y): 
191         """ x.__rdiv__(y) <==> y/x """
192         pass
193 
194     def __repr__(self): 
195         """转化为解释器可读取的形式 """
196         """ x.__repr__() <==> repr(x) """
197         pass
198 
199     def __str__(self): 
200         """转换为人阅读的形式,如果没有适于人阅读的解释形式的话,则返回解释器课阅读的形式"""
201         """ x.__str__() <==> str(x) """
202         pass
203 
204     def __rfloordiv__(self, y): 
205         """ x.__rfloordiv__(y) <==> y//x """
206         pass
207 
208     def __rlshift__(self, y): 
209         """ x.__rlshift__(y) <==> y<<x """
210         pass
211 
212     def __rmod__(self, y): 
213         """ x.__rmod__(y) <==> y%x """
214         pass
215 
216     def __rmul__(self, y): 
217         """ x.__rmul__(y) <==> y*x """
218         pass
219 
220     def __ror__(self, y): 
221         """ x.__ror__(y) <==> y|x """
222         pass
223 
224     def __rpow__(self, x, z=None): 
225         """ y.__rpow__(x[, z]) <==> pow(x, y[, z]) """
226         pass
227 
228     def __rrshift__(self, y): 
229         """ x.__rrshift__(y) <==> y>>x """
230         pass
231 
232     def __rshift__(self, y): 
233         """ x.__rshift__(y) <==> x>>y """
234         pass
235 
236     def __rsub__(self, y): 
237         """ x.__rsub__(y) <==> y-x """
238         pass
239 
240     def __rtruediv__(self, y): 
241         """ x.__rtruediv__(y) <==> y/x """
242         pass
243 
244     def __rxor__(self, y): 
245         """ x.__rxor__(y) <==> y^x """
246         pass
247 
248     def __sub__(self, y): 
249         """ x.__sub__(y) <==> x-y """
250         pass
251 
252     def __truediv__(self, y): 
253         """ x.__truediv__(y) <==> x/y """
254         pass
255 
256     def __trunc__(self, *args, **kwargs): 
257         """ 返回数值被截取为整形的值,在整形中无意义 """
258         pass
259 
260     def __xor__(self, y): 
261         """ x.__xor__(y) <==> x^y """
262         pass
263 
264     denominator = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
265     """ 分母 = 1 """
266     """the denominator of a rational number in lowest terms"""
267 
268     imag = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
269     """ 虚数,无意义 """
270     """the imaginary part of a complex number"""
271 
272     numerator = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
273     """ 分子 = 数字大小 """
274     """the numerator of a rational number in lowest terms"""
275 
276     real = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
277     """ 实属,无意义 """
278     """the real part of a complex number"""
279 
280 int
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