数字类型

from numpy import * import operator def spliting(): print('--'*20) ''' def greatDataSet(): group = array([(1.0,1.1),(1.0,1.0),(0,0),(0,0.1)]) labels = ['A','A','B','B'] return group, labels

print(random.rand(4,4)) # 生成随机数 randMat = mat(random.rand(4,4)) print(randMat) # 转化为矩阵 invRandMat = randMat.I # 实现矩阵求逆 print(randMat * invRandMat) # 矩阵与逆矩阵相乘的结果 myEye = randMat * invRandMat print(myEye - eye(4)) # eye(4)创建单位矩阵 ''' print(int(3.14)) # 3 print(float(3)) # 3.0 print(str('a\tb')) # a b print(repr('a\tb')) # 'a\tb' num = 1/3.0 print('%e' % num) # 3.333333e-01 print('%4.2f' % num) # 0.33 print('{0:4.2f}'.format(num)) # 0.33 print(1 == 2 < 3) # False print(1 == 1 < 3) # True

from future import devision

print(10/4) # 2.5 print(10//4) # 2 print(10/4.0) # 2.5 print(10//4.0) # 2.0 import math print(math.floor(4.2)) # 4 print(math.floor(4.6)) # 4 print(math.floor(-4.6)) # -5 print(math.floor(-4.2)) # -5 print(math.trunc(4.2)) # 4 print(math.trunc(4.6)) # 4 print(math.trunc(-4.6)) # -4 print(math.trunc(-4.2)) # -4 print(round(4.2)) # 4 print(round(4.6)) # 5 print(round(-4.2)) # -4 print(round(-4.6)) # -5

spliting()

print(0o1,0o20) # 1,16 print(0x01,0x10) # 1,16 print(0b01,0b10000) # 1,16 print(oct(64)) # 0o100 print(bin(64)) # 0b1000000 print(hex(64)) # 0x40 print(int('64')) # 64 print(int('100',8)) # 64 print(int('1000000',2))# 64 print(eval（'64')) # 64 print(eval（'0o100')) # 64 print(eval（'0x40')) # 64 print('{0:o},{1:x},{2:b}'.format(64,64,64)) # 100,40,1000000 print('%x %o %X' %(255,64,255)) x = 1 print(bin(x)) # 0b1 print(bin(2)) # 0b10 print(x<<2,bin(x<<2)) # 4, 0b100 print(x | 2 ,bin(x | 2)) # 3 0b11 print(x & 2,bin(x & 2)) # 0 0b0 x = 0xff print(bin(x)) # 0b11111111 print(x^0b10101010) # 85 print(bin(x^0b10101010)) # 0b1010101 print(int('1010101',2)) # 85 print(hex(85)) # 0x55 x = 99 print(bin(99),x.bit_length()) # 0b1100011 7 print(bin(256),(256).bit_length()) # 0b100000000 9 print(len(bin(256))) # 11 print(len(bin(99))) # 9 print((99).bit_length()) # 7

spliting()

import math print(math.pi,math.e) # 3.141592653589793 2.718281828459045 print(math.sin(2 * math.pi /180)) # 0.03489949670250097 print(math.sqrt(144),math.sqrt(2)) # 12.0 1.4142135623730951 print(pow(2,4),2**4)# 16 16 print(abs(-45.4),sum((3,4,5))) # 45.4 12 sum作用一个数字序列 print(min(1,3,4,2),max(3,1,4,2)) # 1 4 print(0.1+0.1+0.1-0.3) # 5.551115123125783e-17 import decimal print(decimal.Decimal('0.1')+decimal.Decimal('0.1')+decimal.Decimal('0.1')-decimal.Decimal('0.3')) # 0.0 print(decimal.Decimal(1)/decimal.Decimal(7)) # 0.1428571428571428571428571429 decimal.getcontext().prec = 2 print(decimal.Decimal(1)/decimal.Decimal(7)) # 0.14 with decimal.localcontext() as ctx: ctx.prec = 4 print(decimal.Decimal(1)/decimal.Decimal(7)) # 0.1429 print(decimal.Decimal(1)/decimal.Decimal(7)) # 0.14

decimal 的localgetcontext可以临时设置小数的精度，结合上下文管理器

with decimal.localcontext() as ctx:

ctx.prec = 4

来临时使用

import fractions print(fractions.Fraction(2.5)) # 小数转化为分数 5/2 print((2.5).as_integer_ratio()) # 5,2

spliting()

x = set('abcde') # 有五个元素 y = set('bdxyz') print(x) # {'a', 'b', 'c', 'd', 'e'} print(x-y) # {'a', 'c', 'e'} a = {'wer'} # 有一个元素 print(x | y) # {'e', 'd', 'a', 'x', 'y', 'b', 'z', 'c'} print(x & y) # {'b', 'd'} print(x^y) # {'e', 'z', 'y', 'a', 'x', 'c'} print(x > y , x < y) # False False z =(x.intersection(y)) print(z) # {'d', 'b'} z.add('spam') print(z) # {'spam', 'd', 'b'} z.update(set(('x','y'))) print(z) # {'b', 'y', 'x', 'spam', 'd'} z.remove('b') print(z) # {'spam', 'x', 'd', 'y'} s = set([1,2,3]) print(s.union(set([4,5]))) # {1, 2, 3, 4, 5} print(s.issubset(range(-5,5))) # True

spliting()

s = {1.23}

print(s.add([1,2,3])) error

print(s.add({1:34})) error

s.add((1.24)) print(s) # {1.23, 1.24} l = [1,1,2,3,4,5,5,6] print(list(set(l))) # [1, 2, 3, 4, 5, 6] a = {1,2,3,4} b = {2,3,5,6} print(2 in a) # True print(a & b) # {2, 3} print(a.intersection(b)) # {2, 3} print(a | b) # {1, 2, 3, 4, 5, 6} print(a.union(b)) # {1, 2, 3, 4, 5, 6} print(a-b) # {1, 4} print(a.difference(b)) # {1, 4} print(a^b) # {1, 4, 5, 6} print(a.symmetric_difference(b)) # {1, 4, 5, 6}

spliting()

print(type(True)) # <class 'bool'> print(isinstance(True,int)) # True print(True + 1) # 2