Best way to handle tabular data

[thaddeusj113]

I'm trying to read in a file line, change some of the line contents, and put the new contents back in the file to replace the old line. What's the best way to do this

[bartonc]

I'm trying to read in a file line, change some of the line contents, and put the new contents back in the file to replace the old line. What's the best way to do this

There are many ways. A "best" way is up for interpretation. Let's see what you are trying to do and see if we can improve on it. That's how things work around here.

Thanks for joining.

[thaddeusj113]

Well I'm really looking for the easiest, not necessarily the best. I have a file that is just 100 rows of 10 columns of numbers seperated by spaces. I want to read in a row, increment one of the columns based on some input, and replace the line with the new data

[bartonc]

Well I'm really looking for the easiest, not necessarily the best. I have a file that is just 100 rows of 10 columns of numbers seperated by spaces. I want to read in a row, increment one of the columns based on some input, and replace the line with the new data

I'd say that the easiest thing would be to do all your manipulation in a 2 dimensional list, then use cpickle to store and retrieve the list from disk. The best way would be to use a true database.

[thaddeusj113]

Thanks for the suggestions, I got it.

[bvdet]

Well I'm really looking for the easiest, not necessarily the best. I have a file that is just 100 rows of 10 columns of numbers seperated by spaces. I want to read in a row, increment one of the columns based on some input, and replace the line with the new data

Handling data stored this way is very straightforward. Pickling the data is a good way, but reading, updating, and writing back to file is also a good way:

fn = r'X:\dir\subdir\data.txt'
 
# Create a list of lists of integers
dataList = [[int(i) for i in line.strip().split()] for line in file(fn).readlines()]
 
'''
.....................................
Manipulate your integer or float data here
.....................................
'''
 
f = file(fn, 'w')
f.write('\n'.join([' '.join([str(i) for i in s]) for s in dataList]))
f.close()