How to read a csv file from a python script?

**somialis** · Mar 23 '07, 06:52 AM

Originally posted by ghostdog74

it does work

Code:

import sys
choice = sys.argv[1]
for line in open("file"):
     line = line.strip().split()
     if choice == line[0]:
          print line[1:][0].split(";")

output :

Code:

# ./test.py 23
['11', '12', '']

Note that your csv file is now colon separated and not comma separated. So you have to change the split() statement.

it dint work even now. Let me tell u wht i did:

1) created a file new.py
2) Wrote the following code:

Code:

import os
import sys
import csv

def main(argv):

    choice = sys.argv[1]
    fp = open("c:\pst\pst_modified\log_4_0.csv",'r')
    for line in fp:
     line = line.strip().split()
     if choice == line[0]:
          print line[1:][0].split(";")

3)i have python23 installed at my system
4) opened the command prompt
5)Moved to the directory where new.py is placed
6)executed the following command
python new.py '23'

whr am i wrong??
./new.py flasgged an error tht "." is not a valid command.

**ghostdog74** · Mar 23 '07, 07:09 AM

Originally posted by somialis

it dint work even now. Let me tell u wht i did:

1) created a file new.py
2) Wrote the following code:

Code:

import os
import sys
import csv

def main(argv):

    choice = sys.argv[1]
    fp = open("c:\pst\pst_modified\log_4_0.csv",'r')
    for line in fp:
     line = line.strip().split()
     if choice == line[0]:
          print line[1:][0].split(";")

3)i have python23 installed at my system
4) opened the command prompt
5)Moved to the directory where new.py is placed
6)executed the following command
python new.py '23'

whr am i wrong??
./new.py flasgged an error tht "." is not a valid command.

try this:

Code:

import os
import sys
import csv ## you are not using this?

filepath = os.path.join("C:\\","pst","pst_modified","log_4_0.csv")

def main():
    choice = sys.argv[1]    
    for line in open(filepath):
     line = line.strip().split()
     if choice == line[0]:
          print line[1:][0].split(";")

main()  ## < --you did not call the main in your last posted script sample.

**somialis** · Mar 23 '07, 08:02 AM

Originally posted by ghostdog74

try this:

Code:

import os
import sys
import csv ## you are not using this?

filepath = os.path.join("C:\\","pst","pst_modified","log_4_0.csv")

def main():
    choice = sys.argv[1]    
    for line in open(filepath):
     line = line.strip().split()
     if choice == line[0]:
          print line[1:][0].split(";")

main()  ## < --you did not call the main in your last posted script sample.

Hi,
it's still not working....thr' s something tht i wud like to tell.
If u put a " print line" statement after
line = line.strip().sp lit()
u'll c that it prints the entire csv file and reaches the end. After tht when u compare choice with line[0] ...the condition does not satisfy becauseline[0] contains the last line of the csv file.

**ghostdog74** · Mar 23 '07, 08:22 AM

Originally posted by somialis

Hi,
it's still not working....thr' s something tht i wud like to tell.
If u put a " print line" statement after
line = line.strip().sp lit()
u'll c that it prints the entire csv file and reaches the end. After tht when u compare choice with line[0] ...the condition does not satisfy becauseline[0] contains the last line of the csv file.

please try this debugging method:

Code:

def main():
    choice = sys.argv[1]    
    for line in open(filepath):
     line = line.strip().split()
     print line, type(line), line[0], line[1]
     raw_input("Press to continue: " )
     if choice == line[0]:
          print line[1:][0].split(";")
main()

please show the output of the above.

**somialis** · Mar 23 '07, 08:26 AM

Originally posted by ghostdog74

please try this debugging method:

Code:

def main():
    choice = sys.argv[1]    
    for line in open(filepath):
     line = line.strip().split()
     print line, type(line), line[0], line[1]
     raw_input("Press to continue: " )
     if choice == line[0]:
          print line[1:][0].split(";")
main()

please show the output of the above.

The output of your code is as follows:

Code:

[',List', 'Of', 'Individual', 'Patches'] <type 'list'> ,List Of
Press to continue:
['1,00;01;'] <type 'list'> 1,00;01;
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "my.py", line 12, in main
    print line, type(line), line[0], line[1]
IndexError: list index out of range

**ghostdog74** · Mar 23 '07, 08:41 AM

Originally posted by somialis

The output of your code is as follows:

Code:

[',List', 'Of', 'Individual', 'Patches'] <type 'list'> ,List Of
Press to continue:
['1,00;01;'] <type 'list'> 1,00;01;
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "my.py", line 12, in main
    print line, type(line), line[0], line[1]
IndexError: list index out of range

hey...you original sample is like this:

Code:

List Of Individual Patches
1 00;01;
2 00;
3 01;
4 02;
5 00;01;02;
6 01;02;
7 01;02;03;04;05;
8 01;02;03;04;05;06;
9 00;01;02;03;05;
10 01;02;03;05;
11 02;03;05;06;
12 04;
13 01;02;03;05;08;09;
14 00;01;02;03;05;09;
15 00;01;02;03;05;09;10;
16 01;02;03;05;08;09;10;
17 01;02;03;05;08;10;
18 08;
19 00;01;02;03;05;08;09;10;
20 02;03;05;06;08;10;
21 11;
22 12;
23 11;12;
24 00;01;02;03;05;14;

so if you have changed your format to like this:

Code:

1,00;01;
2,00;
...
..

then surely it doesn't work. you have to modify the code. i give you a hint on where to change:

Code:

....
    for line in open(filepath):
     line = line.strip().split()  <---here.
....

**somialis** · Mar 23 '07, 08:47 AM

Originally posted by ghostdog74

hey...you original sample is like this:

Code:

List Of Individual Patches
1 00;01;
2 00;
3 01;
4 02;
5 00;01;02;
6 01;02;
7 01;02;03;04;05;
8 01;02;03;04;05;06;
9 00;01;02;03;05;
10 01;02;03;05;
11 02;03;05;06;
12 04;
13 01;02;03;05;08;09;
14 00;01;02;03;05;09;
15 00;01;02;03;05;09;10;
16 01;02;03;05;08;09;10;
17 01;02;03;05;08;10;
18 08;
19 00;01;02;03;05;08;09;10;
20 02;03;05;06;08;10;
21 11;
22 12;
23 11;12;
24 00;01;02;03;05;14;

so if you have changed your format to like this:

Code:

1,00;01;
2,00;
...
..

then surely it doesn't work. you have to modify the code. i give you a hint on where to change:

Code:

....
    for line in open(filepath):
     line = line.strip().split()  <---here.
....

i haven't changed the format. My csv file is the same as it was before.It's like this only:

List Of Individual Patches
1 00;01;
2 00;
3 01;
4 02;
5 00;01;02;
6 01;02;
7 01;02;03;04;05;
8 01;02;03;04;05; 06;
9 00;01;02;03;05;
10 01;02;03;05;
11 02;03;05;06;
12 04;
13 01;02;03;05;08; 09;
14 00;01;02;03;05; 09;
15 00;01;02;03;05; 09;10;
16 01;02;03;05;08; 09;10;
17 01;02;03;05;08; 10;
18 08;
19 00;01;02;03;05; 08;09;10;
20 02;03;05;06;08; 10;
21 11;
22 12;
23 11;12;
24 00;01;02;03;05; 14;
25 00;01;02;03;05; 09;14;
26 00;01;02;03;05; 08;09;10;14;
27 00;01;02;03;05; 17;
28 00;01;02;03;05; 09;17;
29 00;01;02;03;05; 08;09;10;17;
30 01;02;03;05;08; 09;10;17;
31 00;01;02;03;05; 09;18;
32 01;02;03;05;08; 09;10;18;

and after executing ur code snippet i got the error message which i posted in the previous post. Dunno in the output where from the comma is coming.

**ghostdog74** · Mar 23 '07, 09:03 AM

look at this error you had previously:

Code:

[',List', 'Of', 'Individual', 'Patches'] <type 'list'> ,List Of
Press to continue:
['1,00;01;'] <type 'list'> 1,00;01;
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "my.py", line 12, in main
    print line, type(line), line[0], line[1]
IndexError: list index out of range

the follwing output line results from "print line, type(line), line[0], line[1]" statement:

Code:

...
['1,00;01;'] <type 'list'> 1,00;01;
...

The "line" value is ['1,00;01;'] after the split. This means it did not split at all. Furthermore, line.strip().sp lit() splits on blanks and since your data have a comma now, it does nothing.
notice the "," after the first "1" ?? that's why i deduced that you csv format is different. If otherwise, then i have no idea at all.

Code:

...
line = line.strip().split(",")
...

**somialis** · Mar 23 '07, 09:06 AM

Originally posted by ghostdog74

look at this error you had previously:

Code:

[',List', 'Of', 'Individual', 'Patches'] <type 'list'> ,List Of
Press to continue:
['1,00;01;'] <type 'list'> 1,00;01;
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "my.py", line 12, in main
    print line, type(line), line[0], line[1]
IndexError: list index out of range

the follwing output line results from "print line, type(line), line[0], line[1]" statement:

Code:

...
['1,00;01;'] <type 'list'> 1,00;01;
...

The "line" value is ['1,00;01;'] after the split. This means it did not split at all. Furthermore, line.strip().sp lit() splits on blanks and since your data have a comma now, it does nothing.
notice the "," after the first "1" ?? that's why i deduced that you csv format is different. If otherwise, then i have no idea at all.

Code:

...
line = line.strip().split(",")
...

hey it worked this time.
thanks a ton!! :)

**ghostdog74** · Mar 23 '07, 09:11 AM

Originally posted by somialis

hey it worked this time.
thanks a ton!! :)

so it's your csv format after all?

**somialis** · Mar 23 '07, 09:17 AM

Originally posted by ghostdog74

so it's your csv format after all?

dint get ur question.
I just included this line

Code:

line = line.strip().split(",")

in place of this

Code:

line = line.strip().split()

**ghostdog74** · Mar 23 '07, 09:22 AM

Originally posted by somialis

dint get ur question.
I just included this line

Code:

line = line.strip().split(",")

in place of this

Code:

line = line.strip().split()

if by doing a split on comma and it works, it means your csv file has commas, right? so that's why i ask is your csv format like this instead:

Code:

1,00;01;
2,00;
....
...

if its not, then a split on comma will not work.

**somialis** · Mar 23 '07, 09:33 AM

Originally posted by ghostdog74

if by doing a split on comma and it works, it means your csv file has commas, right? so that's why i ask is your csv format like this instead:

Code:

1,00;01;
2,00;
....
...

if its not, then a split on comma will not work.

ok...now i understood!!
Thanks a lot!!

How to read a csv file from a python script?

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