Python学习第十三天

摘要: 将练习的例子贴出来 留着学习

#!/usr/bin/python

#filename:test13.py

class Reverse:

def __init__(self,data):

self.data = data

self.index = len(data)

def __iter__(self):

return self

def __next__(self):

if self.index == 0:

raise StopIteration

self.index = self.index - 1

return self.data[self.index]

rev = Reverse('spam')

print (iter(rev))

for char in rev:

print(char)

print(rev.data)

def reverse(data):

for index in range(len(data)-1,-1,-1):

yield data[index]

for char in reverse('golf'):

print(char)

print(sum(i*i for i in range(10)))

xvec = [10,20,30]

yvec = [7,5,3]

print (sum(x*y for x,y in zip(xvec,yvec)))

from math import pi,sin

since_table = {x:sin(x*pi/180) for x in range(0,91)}

print(since_table)

data = 'golf'

alist = list(data[i] for i in range(len(data)-1,-1,-1))

print(alist)

#!/usr/bin/python

import os

print(dir(os))

print(os.getcwd())

os.system('mkdir 20160328')

import shutil

#shutil.copyfile('myfile.txt','myfile_copy.txt')

#shutil.move('myfile_copy.txt','20160328')

import glob

filepy = glob.glob('*.py')

print(filepy)

import sys

print(sys.argv)

sys.stderr.write('Warning,log file not found starting a new one\n')

import re

p = re.findall(r'\bf[a-z]*','which foot or hand fell fastest')

print(p)

pa = re.sub(r'(\b[a-z]+) \1',r'\1','cat in the the hat')

print(pa)

pat = 'tea for too'.replace('too','two')

print(pat)

import math

cosx = math.cos(math.pi / 4)

print(cosx)

print(math.log(1024,2))

import random

a = random.choice(['apple','pear','banana'])

print(a)

b = random.sample(range(100),10)

print(b)

print(random.random())

print(random.randrange(6))

import statistics

data = [1,2,3,4,5,5,5,6,7.1]

print(statistics.mean(data))

print(statistics.median(data))

print(statistics.variance(data))