《Python核心编程》答案 第9章

filename = raw_input()
f = open(filename)
for eachLine in f:
    if eachLine[0] == ‘#‘:
        continue
    print eachLine,
f.close()

filename = raw_input()
f = open(filename)
for eachLine in f:
    if ‘#‘ not in eachLine:
        print eachLine,
    elif eachLine[0] == ‘#‘:
        continue
    else:
        ans = ""
        for i in eachLine:
            if i == ‘#‘:
                break
            ans += i
        print ans
f.close()

print ‘Please input number N and file F, we will display first N lines for your file‘
n = int(raw_input(‘N: ‘))
fname = raw_input(‘F: ‘)
f = open(fname)
for eachLine in f:
    if n == 0:
        break
    print eachLine,
    n -= 1
f.close()

print ‘Enter a filename, we will display the number of lines of this file.‘
fname = raw_input()
f = open(fname)
count = 0
for eachLine in f:
    count += 1
print ‘This file has %d line(s).‘ % count
f.close()

fname = raw_input(‘Enter a filename: ‘)
f = open(fname)
count = 0
for eachLine in f:
    count += 1
    print eachLine,
    if count % 25 == 0:
        raw_input(‘Press anykey to continue‘)
f.close()

fname = raw_input()
f = open(fname)
sum_of_score = 0.0
count = 0
for eachLine in f:
    sum_of_score += float(eachLine)
    count += 1
avg_of_score = sum_of_score / count
if 90 <= avg_of_score <= 100:
    print ‘A‘
elif 80 <= avg_of_score <= 89:
    print ‘B‘
elif 70 <= avg_of_score <= 79:
    print ‘C‘
elif 60 <= avg_of_score <= 69:
    print ‘D‘
else:
    print ‘F‘

print ‘Enter two file name to compare (suppose two file has same rows)‘
f1name = raw_input(‘file A: ‘)
f2name = raw_input(‘file B: ‘)
f1 = open(f1name)
f2 = open(f2name)
line = 0
same = True
for eachLine in f1:
    line += 1
    f2Line = f2.next()
    if eachLine == f2Line:
        continue
    else:
        same = False
        col = 0
        for i in eachLine:
            if i != f2Line[col]:
                break
            col += 1
        col += 1
        break
if same:
    print ‘Two files are the same‘
else:
    print ‘The first different occurs %d line %d column.‘ % (line, col)

f = open(‘/etc/services‘)
print ‘%17s\t%5s\t%5s‘ % (‘name‘, ‘port‘, ‘protocol‘)
for eachLine in f:
    if eachLine[0] in (‘#‘, ‘\n‘):
        continue
    data = eachLine.split()
    name = data[0]
    port = data[1].split(‘/‘)[0]
    protocol = data[1].split(‘/‘)[1]
    print ‘%17s\t%5s\t%5s‘ % (name, port, protocol)
f.close()

mname = raw_input(‘Enter a module name: ‘)
exec compile(‘import ‘ + mname, ‘‘, ‘single‘)
exec compile(‘a = dir(‘+mname+‘)‘, ‘‘, ‘single‘)
print "The attributes of", mname
print ‘%10s\t%10s\t%10s‘ % (‘name‘, ‘type‘, ‘value‘)
for eachAttr in a:
    exec compile(‘value = ‘ + mname + ‘.‘ + eachAttr, ‘‘, ‘single‘)
    print ‘%10s\t%10s\t%10s‘ % (eachAttr, type(eachAttr), value)

import os

print ‘Welcome URL bookmark manager‘
hasdata = False
if os.path.exists(‘data.txt‘):
    datafile = open(‘data.txt‘, ‘r+‘)
    hasdata = True
else:
    datafile = open(‘data.txt‘, ‘w‘)

prompt = """
(A)dd
(U)pdate
(D)elete
(S)earch
(Q)uit
select one:
"""
data = []
if hasdata:
    temp = datafile.read().split(‘\n‘)
    for t in temp:
        data.append(t.split(‘ ‘))

while True:
    option = raw_input(prompt).lower()[0]

    if option == ‘a‘:
        site_name = raw_input(‘Site name: ‘)
        url_address = raw_input(‘URL address: ‘)
        description = raw_input(‘One line description(optional): ‘)
        data.append([site_name, url_address, ‘"‘+description+‘"‘])
    elif option == ‘u‘:
        site_name = raw_input(‘Enter the site name you want to update its url: ‘)
        url_address = raw_input(‘New url: ‘)
        for eachData in data:
            if eachData[0] == site_name:
                eachData[1] = url_address
                print ‘update succeed‘
                break
        else:
            print ‘no such site name‘
    elif option == ‘d‘:
        site_name = raw_input(‘Enter the site name you want to delete: ‘)
        for i in range(len(data)):
            if data[i][0] == site_name:
                del data[i]
                print ‘delete succeed‘
                break
        else:
            print ‘no such site name‘
    elif option == ‘s‘:
        keyword = raw_input(‘Enter the keyword in site name or url address: ‘)
        findit = False
        for eachData in data:
            for eachItem in eachData:
                if keyword in eachItem:
                    print ‘Site name: %s, URL address: %s, description: %s‘ % (eachData[0],eachData[1],eachData[2])
                    findit = True
                    break
            if findit:
                break
        if not findit:
            print ‘cannot find %s‘ % keyword
    elif option == ‘q‘:
        ans = []
        for eachData in data:
            ans.append(‘ ‘.join(eachData))
        ans = ‘\n‘.join(ans)
        datafile.seek(0)
        datafile.truncate()
        datafile.write(ans)
        datafile.close()
        break

from sys import argv
print "# of args", len(sys.argv)
print "args:", sys.argv

from sys import argv
if len(argv) == 2:
    f = open(‘data.txt‘, ‘r+‘)
    for eachLine in f:
        print eachLine,
    f.seek(0)
    f.truncate()
    f.close()
else:
    n1 = argv[1]
    n2 = argv[3]
    op = argv[2]
    if op == ‘+‘:
        ans = float(n1) + float(n2)
    elif op == ‘-‘:
        ans = float(n1) - float(n2)
    elif op == ‘*‘:
        ans = float(n1) * float(n2)
    elif op == ‘/‘:
        ans = float(n1) / float(n2)
    elif op in (‘**‘, ‘^‘):
        ans = float(n1) ** float(n2)

    if ans == int(ans):
        ans = int(ans)
    print ans
    f = open(‘data.txt‘, ‘a+‘)
    f.write(‘%s %s %s\n‘ % (n1, op, n2))
    f.write(str(ans) + ‘\n‘)
    f.close()

print ‘Input 2 file name, we will copy content from file1 to file2: ‘
f1name = raw_input(‘File 1: ‘)
f2name = raw_input(‘File 2: ‘)
f1 = open(f1name)
f2 = open(f2name, ‘w‘)
f2.write(f1.read())

fname = raw_input(‘Enter file name: ‘)
f = open(fname, ‘r+‘)
content = f.readlines()
index = 0
while True:
    if (len(content[index]) > 80) and (index < len(content)-1):
        content[index+1] = content[index][80:].strip() + content[index+1].strip() + ‘\n‘
        content[index] = content[index][:80] + ‘\n‘
    elif (len(content[index]) > 80) and (index >= len(content)-1):
        content.append(content[index][80:])
        content[index] = content[index][:80] + ‘\n‘
    index += 1
    if index >= len(content):
        break

f.seek(0)
f.truncate()
f.write(‘‘.join(content))
f.close()

print ‘Welcome to crude and elementary text file editor‘
prompt = """
(C)reate file
(D)isplay file
(E)dit file
(S)ave file
(Q)uit

select one:
"""
option = raw_input(prompt).lower()[0]
content = []
while True:
    if option == ‘c‘:
        filename = raw_input(‘Enter the file name: ‘)
        print ‘Please enter file content, end with ctrl+c‘
        try:
            while True:
                content.append(raw_input(‘->‘))
        except KeyboardInterrupt:
            print ‘create succeed!‘
    elif option == ‘d‘:
        for eachLine in content:
            print eachLine
    elif option == ‘e‘:
        line = int(raw_input(‘Which line you want to edit? ‘))
        print ‘The new content:‘
        ncontent = raw_input(‘->‘)
        content[line-1] = ncontent
    elif option == ‘s‘:
        f = open(filename, ‘w‘)
        f.write(‘\n‘.join(content))
        f.close()
    elif option == ‘q‘:
        break
    else:
        print ‘error option‘
    option = raw_input(prompt).lower()[0]

print ‘Enter a byte value(0-255) and a filename‘
print ‘We will display the number of times that byte appers in the file.‘
value = int(raw_input(‘Byte value(0-255): ‘))
fname = raw_input(‘Filename: ‘)
f = open(fname)
ch = chr(value)
count = 0
for each in f.read():
    if each == ch:
        count += 1
print "The byte value %d(‘%s‘) appears %d times in this file."% (value, ch, count)
f.close()

from random import randint

def mybin(n):
    ans = ‘‘
    while n != 0:
        ans = str(n % 2) + ans
        n = n / 2
    for i in range(8-len(ans)):
        ans = ‘0‘ + ans
    return int(ans)

byte_value = int(raw_input(‘Byte value: ‘))
times = int(raw_input(‘Times: ‘))
total_byte = int(raw_input(‘Total byte: ‘))

ans = []
for i in range(total_byte - times):
    num = byte_value
    while num == byte_value:
        num = randint(0,255)
    num = mybin(num)
    ans.append(str(num))

byte_value = mybin(byte_value)

for i in range(times):
    position = randint(0, total_byte - times)
    ans.insert(position, str(byte_value))

ans = ‘ ‘.join(ans)
f = open(‘data.txt‘, ‘w‘)
f.write(ans)
f.close()