Exercise 20: Functions And Files

from sys import argv
script, input_file = argv
def print_all(f):
    print f.read()
    def rewind(f):
    f.seek(0)
def print_a_line(line_count, f):
    print line_count, f.readline()
current_file = open(input_file)
print "First let's print the whole file:
"
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 = 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)

readline() 会读空行的 , readlines() 直接读到文件结尾。

line 需要line.strip()