[Tutor] readline() problem

Marilyn Davis marilyn at deliberate.com
Wed Feb 11 17:33:49 EST 2004


On Wed, 11 Feb 2004, Ron Alvarado wrote:

> Here's what I'm getting when I try readline(). What an I doing wrong?
> 
> >>> data = open('bData.csv', 'r')
> >>> num = True
> >>> while num != "":
>  data = data.readline()
>  print data

The first call to data.readline() will read the first line of the
file, make a string of it, and then rename 'data' to be that
string/line.  From then on, all is lost because you have lost your
identifier that points to the file.  Next time around the loop, 'data'
is that last line/string and it doesn't know anything about the file
or 'readline'.

The best solution is to rename the file:

file = open('bData.csv', 'r')
num = True
while num != "":
    data = file.readline()
    print data

However, this will cause an infinite loop because num never becomes
"".  So you still have a problem to work out.

Good luck!

Marilyn Davis



> 
>  
> Part number Description Item Cost 1104 1105 1118
> 
> 
> Traceback (most recent call last):
>   File "<pyshell#7>", line 2, in -toplevel-
>     data = data.readline()
> AttributeError: 'str' object has no attribute 'readline'
> >>> 
> 
> 
> _______________________________________________
> Tutor maillist  -  Tutor at python.org
> http://mail.python.org/mailman/listinfo/tutor
> 

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