code:

input_file = 'bird.inp'
f_in = open(input_file, "r")

lines=f_in.readlines()
f_in.close()

for line in lines:

code:
fvv@no:~/tmp$ cat tmp.txt 
a
b
c
d
e
fvv@no:~/tmp$ cat tmp.py
f = open('tmp.txt')

for line in f:
    print line
    f.next()
fvv@no:~/tmp$ python tmp.py 
a

c

e

Traceback (most recent call last):
  File "tmp.py", line 5, in <module>
    f.next()
StopIteration
  

Quote:

---

ужас. 2. у тебя сдвигают итератор и for, и next, ты используешь то, что в данном случае файл сам себе итератор, ... в общем, ужас.

---

Quote:

---

A file object is its own iterator, for example iter(f) returns f (unless f is closed). When a file is used as an iterator, typically in a for loop (for example, for line in f: print line), the next() method is called repeatedly. This method returns the next input line, or raises StopIteration when EOF is hit when the file is open for reading (behavior is undefined when the file is open for writing). In order to make a for loop the most efficient way of looping over the lines of a file (a very common operation), the next() method uses a hidden read-ahead buffer. As a consequence of using a read-ahead buffer, combining next() with other file methods (like readline()) does not work right.

---

code:

from math import *
input_file = 'bird.inp'
f_in = open(input_file, "r")

lines=f_in.readlines()
f_in.close()

for line in lines:
	lines.next()

code:

  File "test.py", line 9, in ?
    lines.next()
AttributeError: 'list' object has no attribute 'next'

code:

cat a.txt 
1
12
13
1244
cat 1.py 
f = open('a.txt')
a = f.readline()

while a:
	print a
	a = f.readline()

f.close()

  

code:

with open ('a.txt') as f:
  a = f.readline ()
  while a:
     print a
     a = f.readline ()