readlines()

[Yong Wang]

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,

[md]

I am not sure which name is designating your source text (db1 or getdata
?). If it is 'getdata' then you will need to iterate over the file
object to grab all of the lines. Try this:

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=[]
for line in getdata.readlines():
data.append(line)
print 'data[0] is', data[0]
print 'data[3] is', data[3]
getdata.close()

Hope this helps,
Mark d.
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,

[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