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:\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=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)
常见问题之Q2: 文件中为什么有3个空行？
函数 readline() 返回一行以 \n 结尾的文件内容， 在你调用print函数的最后增加一个逗号','，用来避免为每一行添加两个换行符 \n
def print_a_line(line_count,f):
print line_count,f.readline(),
转载于:https://www.cnblogs.com/luckyraye/p/7819572.html
