readlines()

[wes weston]

Yong Wang wrote:
> Hi,
>    I use readlines() to read one data file. Python automatically parses the read contents
> into a list of lines. When I used list[0] to print out the 1st line, it is ok. When I use
> the list index 2 to print out the 2nd line , there is an error mesage. I only need one line of
> input data file in the middle of the file. For example, I have data file like: 
> ---------------------------------------------------------------------------
>           Timestamp: Sat Aug  7 11:14:57 AM
>     Adapter Address: 00:60:08:2A:C9:5A
>          IP Address: 165.91.10.244
>        Directory ID: 0675392c736079cfd81a55028df3cb43
>         Domain Name: bdanwood.dsl.tamu.edu
>     DHCP/NIM Action: lease renewed
>            Comments: 
> ---------------------------------------------------------------------------
>           Timestamp: Sat Aug  7 11:15:56 PM
>     Adapter Address: 00:60:08:2A:C9:5A
>          IP Address: 165.91.10.244
>       Directory ID: 0675392c736079cfd81a55028df3cb43
>         Domain Name: bdanwood.dsl.tamu.edu
>     DHCP/NIM Action: lease renewed
>            Comments: 
> ---------------------------------------------------------------------------
> 
> I have some codes:
>     .......
> for line in db1:
>    (ip, mac) = string.split(line)
>     print 'ip is ', ip
>     run = 'dhcpacct --ip=%s  > tt1'
>     os.system(run)
>     getdata = open('tt1', 'r')
>     data    = getdata.readlines()
>     print 'data[0] is', data[0]
>     print 'data[3] is', data[3]
>     getdata.close()
>  
> When run the codes, I got:
> data[0] is ---------------------------------------------------------------------------
> 
> data[3] is
> Traceback (innermost last):
>   File "com1", line 64, in ?
>     print 'data[3] is', data[3]
> IndexError: list index out of range
> 
>     How can I fix it ?
> 
>     Thanks,
> 
> 
Yong,
    In general, for debugging, why not use

    for i in range(len(data)):
       print 'data[',i,'] is',data[i]

wes