笨办法学Python（learn python the hard way）--练习程序11-20

#ex11.py
1 print("How old are you?",end=''),
 age = input()
 print("How tall are you?",end=''),
 height = input()
 print("How much do you weigh?",end=''),
 weight = input()

 print(f"So,you're {age} old,{height} tall and {weight} heavy.")

#ex12.py
1 age = input("How old are you?")
 height = input("How tall are you?")
 weight = input("How much do you weigh?")

 print(f"So,you're {age} old,{height} tall and {weight} heavy.")

#ex13.py
1 from sys import argv

 script, first, second, third = argv
 a=input("what's your name?")
 print(a)
 print("The script is called:", script)
 print("Your first variable is:", first)
 print("Your second variable is:", second)
 print("Your third variable is:", third)

 #ex14.py
 1 from sys import argv

 script, user_name = argv
 prompt = '> '

 print("Hi %s, I'm the %s script."%(user_name, script))
 print("I'd like to ask you a few questions.")
 print("Do you like me %s?"%user_name)
 likes = input(prompt)

 print("Where do you live %s?"%user_name)
 lives = input(prompt)

 print("What kind of computer do you have?")
 computer = input(prompt)

 print("""
 Alright,so you said %r about liking me.
 You live in %r. Not sure where that is.
 And you have a %r computer. Nice.
 """%(likes, lives, computer))

 #ex15.py
 1 from sys import argv

 script, filename = argv

 txt = open(filename)

 print("Here's your file %r:"%filename)
 print(txt.read())
 txt.close()

 print("Type the filename again:")
 file_again = input("> ")

 txt_again = open(file_again)

 print(txt_again.read())
 txt_again.close()

附ex15_sample：This is stuff I typed into a file.
It is really cool stuff.
Lots and lots of fun to have in here.

 #ex16.py
 1 from sys import argv

 script, filename = argv

 print("We're going to erase %r."%filename)
 print("If you don't want that, hit CTRL-C(^C).")
 print("If you do want that, hit RETURN.")

 #input作用是中断程序，选择是否要删除文件内容
 input("?")

 print("Opening the file...")
 #'w'是open的参数，默认是读，只有特别指定才可以进入写操作，写操作是先删除再新建，所以后面的truncate实际是不起作用的
 target = open(filename, 'w')

 print("Truncating the file. Goodbye!")
 target.truncate()

 print("Now I'm going to ask you for three lines.")

 line1 = input("line 1: ")
 line2 = input("line 2: ")
 line3 = input("line 3: ")

 print("I'm going to write these to the file.")

 target.write(line1)
 target.write("\n")
 target.write(line2)
 target.write("\n")
 target.write(line3)
 target.write("\n")

 print("And finally, we close it.")
 target.close()

 #ex17.py
 1 from sys import argv
 from os.path import exists

 script, from_file, to_file = argv

 print("Copying from %s to %s" %(from_file, to_file))

 # we could do these two on one line too, how?
 #indata = open(from_file).read()
 input = open(from_file)
 indata = input.read()

 print("The input file is %d bytes long"%len(indata))

 print("Does the output file exist?%r" %exists(to_file))
 print("Ready, hit RETURN to continue, CTRL-C to abort.")
 input("??")

 output = open(to_file, 'w')
 output.write(indata)
 print("Alright,all done.")

 output.close()
 input.close()

 #ex18.py
 1 # this one is like your scripts with argv
 def print_two(*args):
  arg1, arg2 = args
  print("arg1: %r, arg2: %r"%(arg1, arg2))

 # ok, that *args is actually pointless, we can just do this
 def print_two_again(arg1, arg2):
  print("arg1: %r, arg2: %r"%(arg1, arg2))

 # this just takes one argument
 def print_one(arg1):
  print("arg1: %r"% arg1)

 # this one takes no arguments
 def print_none():
  print("I got nothin'.")

 print_two("Zed","Shaw")
 print_two_again("Zed","Shaw")
 print_one("Frist!")
 print_none()

 #ex19.py
 1 # 函数里边的变量和脚本里边的变量之间是没有连接的
 def cheese_and_crackers(cheese_count, boxes_of_crackers):
     print("You have %d cheeses!"%cheese_count)
     print("You have %d boxes of crackers!"%boxes_of_crackers)
     print("Man that's enough for a party!")
     print("Get a blanket.\n")

 print("We can just give the function numbers directly:")
 cheese_and_crackers(20,30)

 print("OR, we can use variables from our script:")
 amount_of_cheese = 10
 amount_of_crackers = 50

 cheese_and_crackers(amount_of_cheese, amount_of_crackers)

 print("We can even do math inside too:")
 cheese_and_crackers(10+20,5+6)

 print("And we can combine the two, variables and math:")
 cheese_and_crackers(amount_of_cheese + 100, amount_of_crackers + 1000)

 #ex20.py
 1 #函数和文件如何一起协作
 from sys import argv
 script, input_file = argv

 #定义函数：将读到的内容打印出来
 def print_all(f):
     print(f.read())

 #定义函数：将光标定位到起始位置
 def rewind(f):
     f.seek(0)

 #定义函数： 将读到的行数及该行内容打印出来
 def print_a_line(line_count, f):
     print(line_count, f.readline())

 #打开文件
 current_file = open(input_file)

 print("First let's print the whole file:\n")

 print_all(current_file)

 print("Now let's rewind, kind of like a tape.")

 rewind(current_file)

 print("Let's print three lines:")

 #current_line = 0
 #current_line += 1
 current_line = 1
 print_a_line(current_line, current_file)

 current_line = current_line + 1
 print_a_line(current_line, current_file)

 current_line = current_line + 1
 print_a_line(current_line, current_file)