Exercise 16 - reading and writing file

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("?")

print("Opening the file...")
target = open(filename, 'w')

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

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

line1 = input("line1: ")
line2 = input("line2: ")
line3 = input("line3: ")

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()

output

D:\>python ex16.py test.txt
We're going to erase 'test.txt'.
If you don't want that, hit CTRL-C (^C).
If you do want that, hit RETURN.
?
Opening the file...
Truncating the file. Goodbye!
Now I'm going to ask you for three lines.
line1: I don't know what to write
line2: Whatever
line3: Just do it then
I'm going to write these to the file.
And finally, we close it.

test.txt

I don't know what to write
Whatever
Just do it then

 优化-减少重复

from sys import argv

script, filename = argv

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

input("?")

print("Opening the file...")
target = open(filename, 'w')

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

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

line1 = input("line1: ")
line2 = input("line2: ")
line3 = input("line3: ")

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

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

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

2019-09-27

17:47:14