Array column separations for beginners
Peter Otten
__peter__ at web.de
Wed Apr 26 10:29:27 EDT 2017
katarin.bern at gmail.com wrote:
> Hi,
> 1. I would like to ask how can I adjust array.csv like this:
> ,,,-00.000146400000, 0.08000,
> ,,,-00.000146200000, 0.00000,
> ,,,-00.000146000000, 0.00000,
> ,,,-00.000145800000, 0.00000,
>
> so I can have in first column -00.000146400000 and in second column
> 0.08000? (thanks, I am begginer).
Have a look at the csv module
https://docs.python.org/dev/library/csv.html
You can use the reader class to read the rows and the writer to write the
result to a new file.
(All code untested)
with open("array.csv") as infile:
reader = csv.reader(infile)
with open("out.csv", "w") as outfile:
writer = csv.writer(outfile)
for row in reader:
writer.writerow([row[3], row[4]])
> 2. How can I pick out information(number) from 20 separate files to one
> file? (thanks!)
Do you know how to extract the number from one file? Put the code into a
function
def pick_number(filename):
... # open the file, extract the number
return number
Then specify the filenames:
sourcefiles = ["foo.txt", "bar.txt", ...]
If the list of filenames is not fixed have a look at the glob module.
https://docs.python.org/dev/library/glob.html
Example:
sourcefiles = glob.glob("/path/to/*.txt") # all txt files in the /path/to
# directory
Finally loop over the files and write out the numbers:
with open("/path/to/outfile.txt", "w") as outfile:
for filename in sourcefiles:
print(pick_number(filename), file=outfile)
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