2.4 使用raw_input()函数得到用户输入.
(a) 创建一段脚本使用raw_input()函数从用户输入得到一个字符串, 然后显示这个用户杠杠输入的字符串.
#coding = utf-8
str1 = raw_input("Enter a string please -->")
print "The string you just entered is: %s" %str1
(b)添加一段类似的代码, 不过这次输入的数值....
# coding = utf-8
num = int(raw_input("Enter a number please -->"))
print "The number you just entered is: %d" %num
2.5 循环和数字
分别使用while和for创建一个循环
(a) 写一个while循环,输出整形为0~10(确保是0~10, 而不是0~9 或1~10)
num = 0
while num <=10:
print num
num += 1
(b) 使用range函数实现(a)
for num in range(0,11): #注意此处range的第二个参数不包含在循环内.
print num
2.6 条件判断, 判断一个数是整数,还是负数,或者0. 开始先用固定的值, 然后修改你的代码支持用户输入数字再进行判断.
#num = 10
num = int(raw_input("Enter a number please -->"))
if num > 0:
print "%d is greater than 0" %num
elif num < 0:
print "%d is smaller than 0" %num
else:
print "%s is equal to 0" %num
2.7 循环和字串, 从用户那里接受一个字符串输入, 然后逐字符显示该字符串. 先用while循环实现,然后再用for循环实现.
(a) # coding = utf-8
str1 = raw_input("Enter a string please -->")
numbers = 0
while numbers <= len(str1)-1:
print str1[numbers]
numbers += 1 # 写这个小片段时, 犯了两个小错误, 1. 忘记numbers自增. 2. 越界一次.
(b) # coding = utf-8
str1 = raw_input("Enter a string please -->")
for ch in str1:
print ch
2.8 循环和操作符. 创建一个包含五个固定数值的列表或元祖, 输入他们的和. 然后修改你的代码为接受用户输入数组, 分别用while 和for循环实现.
(a) while
# coding = utf-8
lt = [1,2,3,4,5,6,7,8,9]
num = 0
total = 0
while num < len(lt):
total += lt[num]
num += 1
(b) for
lt = [1,2,3,4,5,6,7,8,9]
total = 0
for num in lt:
total += num
(c) 用户输入创建列表
lt = []
i = 0
total = 0
while i < 10:
print "You need enter 10 numbers to create the list %d left" %(10-i)
num = int(raw_input('Enter your number -->'))
lt.append(num)
i += 1
(d)使用reduce实现
lt = [1,2,3,4,5,6,7,8,9,10]
def addup(num1, num2):
return num1 + num2
total = reduce(addup,lt) #竟然如此简单加列表构造在一起一共4行代码.
2.9 循环和操作符, 创建一个包含五个固定数值的列表货元组, 输入他们的平均值.
lt = [1,2,3,4,5,6,7,8,9,10]
avg = float(sum(lt)) / len(lt)
2.10 带循环和条件判断的用户输入, 使用raw_input函数来提示用户输入一个1和100之间的数, 如果用户输入满足这个条件,显示成功并退出. 否则提示一个错误信息然后再次提示用户输入数值, 知道满足条件为止
while True:
num = int(raw_input("Enter a number between 1 and 100 -->"))
if 1 < num < 100:
print "bingo"
else:
print "The number you entered is not between 1 and 100."
2.11 带文本菜单的程序: 写一个带文本菜单的程序, 菜单项如下: (1)取五个数的和, (2)取五个数的平均值, (x)退出. 由用户做一个选择,然后执行相应的功能, 当用户选择脱时程序结束.
lt = range(1,11)
action = raw_input('What do you wanna do with this list,
(1) "sum" to get the sum.
(2) "avg" to get the average.
(3) "x" to quit -->')
if action == 'sum':
print "The sum of the list is %d" %sum(lt)
elif action == 'avg':
print "The average value of the list is %f" %(float(sum(lt)) / len(lt))
elif action.lower() == "x":
exit()
2.15 元素排序
从大到小:
a = int(raw_input("Enter a number for a -->"))
b = int(raw_input("Enter a number for b-->"))
c = int(raw_input("Enter a number for c-->"))
if a >= b:
if b >=c:
print a,b,c
elif a >=c:
print a,c,b
else:
print c,a,b
elif a >= c:
print b,a,c
elif b >=c:
print b,c,a
else:
print c,b,a
从小到大:
if a >= b:
if b >=c:
print c,b,a
elif a >=c:
print b,c,a
else:
print b,a,c
elif a >= c:
print c,a,b
elif b >=c:
print a,c,b
else:
print a,b,c