python 练习

1.    实现1-100的所有的和

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author :Alvin.xie
# @Time :2017-10-26 15:41
# @file :sum.py

# 方法1 for循环实现
 sum1 = 0
 for i in xrange(1,101):
 sum1 += i

 print "1+2+3+...+100= %d" % sum1

# 方法2 while循环实现

sum2 = 0
n = 0
while True:
    sum2 += n
    n += 1
    if n>100: break

print "1+2+3+...+100= %d" % sum2

执行结果：
1+2+3+...+100= 5050
1+2+3+...+100= 5050

2.    实现1-500所有奇数的和

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author :Alvin.xie
# @Time :2017-10-26 15:57
# @file :qishu.py

sum1 = 0
for i in xrange(1,501):
    if i % 2 != 0:
        sum1 += i

print "1-500所有奇数的和:%d " % sum1

sum2 = 0
for i in xrange(1,501,2):
        sum2 += i

print "1-500所有奇数的和:%d " % sum2

执行结果：
1-500所有奇数的和:62500 
1-500所有奇数的和:62500 
3.    求1+ 2! + 3! + 4! + ……20！的和

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author :Alvin.xie
# @Time :2017-10-26 13:35
# @file :jiechen.py

# 方法1
i = 1
sum1 = 0
sum2 = 1
for i in xrange(1,21):
    sum2 = sum2 * i
    sum1 = sum1 + sum2
    print "1-%d的阶乘和：%s" % (i, sum1)

# 方法2
import math
sum1 = 0
for i in xrange(1,21):
    sum1 += math.factorial(i)
    print "1-%d的阶乘和：%s" % (i, sum1)

执行结果：
1-1的阶乘和：1
1-2的阶乘和：3
1-3的阶乘和：9
1-4的阶乘和：33
1-5的阶乘和：153
1-6的阶乘和：873
1-7的阶乘和：5913
1-8的阶乘和：46233
1-9的阶乘和：409113
1-10的阶乘和：4037913
1-11的阶乘和：43954713
1-12的阶乘和：522956313
1-13的阶乘和：6749977113
1-14的阶乘和：93928268313
1-15的阶乘和：1401602636313
1-16的阶乘和：22324392524313
1-17的阶乘和：378011820620313
1-18的阶乘和：6780385526348313
1-19的阶乘和：128425485935180313
1-20的阶乘和：2561327494111820313

4.    对指定一个list进行排序[2,32,43,453,54,6,576,5,7,6,8,78,7,89]

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author :Alvin.xie
# @Time :2017-10-26 16:06
# @file :paixu.py

# 方法1
alist = [2,32,43,453,54,6,576,5,7,6,8,78,7,89]
alist.sort()
print "sort方法实现"
print alist
print('*' * 51)
# 插入排序
lists = [2,32,43,453,54,6,576,5,7,6,8,78,7,89]
def insert_sort(lists):
    count = len(lists)
    for i in range(1, count):
        key = lists[i]
        j = i - 1
        while j >= 0:
            if lists[j] > key:
                lists[j + 1] = lists[j]
                lists[j] = key
            j -= 1
    print "插入排序"
    print lists

# 希尔排序
def shell_sort(lists):
    count = len(lists)
    step = 2
    group = count / step
    while group > 0:
        for i in range(0, group):
            j = i + group
            while j < count:
                k = j - group
                key = lists[j]
                while k >= 0:
                    if lists[k] > key:
                        lists[k + group] = lists[k]
                        lists[k] = key
                    k -= group
                j += group
        group /= step
    print "希尔排序"
    print lists

#冒泡排序
def bubble_sort(lists):
    count = len(lists)
    for i in range(0, count):
        for j in range(i + 1, count):
            if lists[i] > lists[j]:
                lists[i], lists[j] = lists[j], lists[i]
    print "冒泡排序"
    print lists

# 选择排序
def select_sort(lists):
    count = len(lists)
    for i in range(0, count):
        min = i
        for j in range(i + 1, count):
            if lists[min] > lists[j]:
                min = j
        lists[min], lists[i] = lists[i], lists[min]
    print "选择排序"
    print lists

# 堆排序
def adjust_heap(lists, i, size):
    lchild = 2 * i + 1
    rchild = 2 * i + 2
    max = i
    if i < size / 2:
        if lchild < size and lists[lchild] > lists[max]:
            max = lchild
        if rchild < size and lists[rchild] > lists[max]:
            max = rchild
        if max != i:
            lists[max], lists[i] = lists[i], lists[max]
            adjust_heap(lists, max, size)

def build_heap(lists, size):
    for i in range(0, (size/2))[::-1]:
        adjust_heap(lists, i, size)

def heap_sort(lists):
    size = len(lists)
    build_heap(lists, size)
    for i in range(0, size)[::-1]:
        lists[0], lists[i] = lists[i], lists[0]
        adjust_heap(lists, 0, i)
    print "堆排序"
    print lists

if __name__ == '__main__':
    insert_sort(lists)
    shell_sort(lists)
    bubble_sort(lists)
    select_sort(lists)
    heap_sort(lists)

执行结果：
sort方法实现
[2, 5, 6, 6, 7, 7, 8, 32, 43, 54, 78, 89, 453, 576]
***************************************
插入排序
[2, 5, 6, 6, 7, 7, 8, 32, 43, 54, 78, 89, 453, 576]
希尔排序
[2, 5, 6, 6, 7, 7, 8, 32, 43, 54, 78, 89, 453, 576]
冒泡排序
[2, 5, 6, 6, 7, 7, 8, 32, 43, 54, 78, 89, 453, 576]
选择排序
[2, 5, 6, 6, 7, 7, 8, 32, 43, 54, 78, 89, 453, 576]
堆排序
[2, 5, 6, 6, 7, 7, 8, 32, 43, 54, 78, 89, 453, 576]