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Core Python Programming Exercises Chapter 5

5-3.

Standard Type Operators. Take test score input from the user and output letter grades

#!/usr/bin/env python
2

#-*- coding:utf-8 -*-
3

#$Id: p0503.py 126 2010-04-20 02:18:07Z xylz $
4

'''
6

This is a 'python' study plan for xylz.
7

'''
9

'''
12

Print the score result.
13

'''
14

def getResultString(score):
15

if score <0 or score > 100: return "ERROR SCORE"
16

if 90 <= score <= 100: return "A"
17

if 80 <= score <= 89: return "B"
18

if 70 <= score <= 79: return "C"
19

if 60 <= score <= 69: return "D"
20

return "F"
21

if __name__ == '__main__':
23

'''
24

Take test score input from the user and output letter grades.
25

'''
26

while True:
27

s = raw_input("Enter an Integer ('exit' or 'quit' for over). \n>>")
28

if s == 'exit' or s == 'quit' : break
29

try:
31

v=int(s)
32

except ValueError,e:
33

print "Error! Not a number. ",
34

else:
35

print v,"=>",getResultString(v)
36

5-4.

Modulus. Determine whether a given year is a leap year, using the following formula: a leap year is one that is divisible by four, but not by one hundred, unless it is also divisible by four hundred. For example, 1992, 1996, and 2000 are leap years, but 1967 and 1900 are not. The next leap year falling on a century is 2400.

#!/usr/bin/env python
2

#-*- coding:utf-8 -*-
3

#$Id: p0504.py 127 2010-04-20 02:19:33Z xylz $
4

'''
6

This is a 'python' study plan for xylz.
7

'''
9

import sys
11

import types
12

'''
14

Determine whether a given year is a leap year.
15

'''
16

def isleapyear(year):
17

if type(year) is not types.IntType: return False
18

if year > 9999 or year <= 0: return False
19

if (year%400 == 0) or ((year%4==0) and (year%100 !=0)):
20

return True
21

return False
22

if __name__ == '__main__':
24

'''
25

Print leap year.
26

'''
27

while True:
28

s = raw_input("Input a 'year' ('exit' or 'quit' for over). \n>>")
29

if s == 'exit' or s == 'quit' :sys.exit(0)
30

try:
32

year=int(s)
33

except ValueError,e:
34

print "Error! Not a number. ",
35

else:
36

print year,"is leap year?",isleapyear(year)
37

5-5.

Modulus. Calculate the number of basic American coins given a value less than 1 dollar. A penny is worth 1 cent, a nickel is worth 5 cents, a dime is worth 10 cents, and a quarter is worth 25 cents. It takes 100 cents to make 1 dollar. So given an amount less than 1 dollar (if using floats, convert to integers for this exercise), calculate the number of each type of coin necessary to achieve the amount, maximizing the number of larger denomination coins. For example, given $0.76, or 76 cents, the correct output would be "3 quarters and 1 penny." Output such as "76 pennies" and "2 quarters, 2 dimes, 1 nickel, and 1 penny" are not acceptable.

#!/usr/bin/env python
2

#-*- coding:utf-8 -*-
3

#$Id: p0505.py 128 2010-04-20 02:22:45Z xylz $
4

'''
6

This is a 'python' study plan for xylz.
7

'''
9

'''
12

get min number of cents
13

'''
14

def getMinNumberOfCents(m):
15

if m < 0 or m >= 1: return (-1,-1,-1,-1)
16

money = round(m*100)
17

yy25 = divmod(money,25)
18

yy10 = divmod(yy25[1],10)
19

yy5 = divmod(yy10[1],5)
20

return (int(yy25[0]),int(yy10[0]),int(yy5[0]),int(yy5[1]))
21

if __name__ == '__main__':
23

'''
24

Calculate the number of basic American coins given a value less than 1 dollar.
25

'''
26

while True:
27

s = raw_input("Input a 'money' between 0 and 1 ('exit' or 'quit' for over). \n>>")
28

if s == 'exit' or s == 'quit' :break
29

try:
31

money=float(s)
32

except ValueError,e:
33

print "Error! Not a number. ",
34

else:
35

print "25 cents: %d\n10 cents: %d\n 5 cents: %d\n 1 cents: %d" % getMinNumberOfCents(money)
36

5-6.

Arithmetic. Create a calculator application. Write code that will take two numbers and an operator in the format: N1 OP N2, where N1 and N2 are floating point or integer values, and OP is one of the following: +, -, *, /, %, **, representing addition, subtraction, multiplication, division, modulus/remainder, and exponentiation, respectively, and displays the result of carrying out that operation on the input operands. Hint: You may use the string split() method, but you cannot use the exal() built-in function.

#!/usr/bin/env python
2

#-*- coding:utf-8 -*-
3

#$Id: p0506.py 129 2010-04-20 02:25:57Z xylz $
4

'''
6

This is a 'python' study plan for xylz.
7

'''
9

import sys
11

'''
13

a two number calculator
14

'''
15

def calculate(s):
16

for c in ('+','-','**','/','%','*'):
17

rs = s.split(c)
18

if rs and len(rs) == 2:
19

one=float(rs[0].strip())
20

two=float(rs[1].strip())
21

if c == '+':return one+two
22

if c == '-':return one-two
23

if c == '**': return one**two
24

if c == '/':
25

if two==0: raise ValueERROR,"ZERO DIVISION"
26

return one/two
27

if c == '%':return one%two
28

if c == '*':return one*two
29

raise ValueError,"ERROR EXPRESSION"
30

raise ValueError,"ERROR EXPRESSION"
31

if __name__ == '__main__':
34

'''
35

Write code that will take two numbers and an operator in the format: N1 OP N2.
36

'''
37

while True:
38

s = raw_input("Input a string expression ('exit' or 'quit' for over). \n>>")
39

if s == 'exit' or s == 'quit' :break
40

try:
42

v = calculate(s)
43

except ValueError,e:
44

print "Error! Not a expression. ",
45

else:
46

print "%s = %s" % (s,v)
47

5-17.

*Random Numbers. Read up on the random module and do the following problem: Generate a list of a random number (1 < N <= 100) of random numbers (0 <= n <= 2³¹-1). Then randomly select a set of these numbers (1 <= N <= 100), sort them, and display this subset.

#!/usr/bin/env python
2

#-*- coding:utf-8 -*-
3

#$Id: p0517.py 130 2010-04-20 02:29:51Z xylz $
4

'''
6

This is a 'python' study plan for xylz.
7

'''
9

import sys
11

import random
12

'''
14

a random demo
15

'''
16

def randomAndSort(m,max):
17

ret = []
18

for i in range(m):
19

ret.append(random.randint(0,max))
20

ret.sort()
21

return ret
22

if __name__ == '__main__':
24

'''
25

Read up on the random module and do the following problem: Generate a list of a random number (1 < N <= 100) of random numbers (0 <= n <= 2e31-1). Then randomly select a set of these numbers (1 <= N <= 100), sort them, and display this subset.
26

'''
27

print randomAndSort(100,sys.maxint)
28

posted on 2010-04-20 10:31 imxylz 閱讀(16825) 評論(0) 編輯收藏所屬分類: Python

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