Search for a specific value in a specific column with Python
I've got a text file that is tab delimited and I'm trying to figure out how to search for a value in a specific column in this file.
I think i need to use the csv import but have been unsuccessful so far. Can someone point me in the right direction?
Thanks!
**Update** Thanks for everyone's updates. I know I could probably use awk for this but simply for practice, I am trying to finish it in python.
I am getting the following error now: if row.split(' ')[int(searchcolumn)] == searchquery: IndexError: list index out of range
And here is the snippet of my code:
#open the directory and find all the files
for subdir, dirs, files in os.walk(rootdir):
for file in files:
f=open(file, 'r')
lines=f.readlines()
for line in lines:
#the first 4 lines of the file are crap, skip them
if linescounter > startfromline:
with open(file) as infile:
for row in infile:
if row.split(' ')[int(searchcolumn)] == searchquery:
开发者_C百科 rfile = open(resultsfile, 'a')
rfile.writelines(line)
rfile.write("\r\n")
print "Writing line -> " + line
resultscounter += 1
linescounter += 1
f.close()
I am taking both searchcolumn and searchquery as raw_input from the user. Im guessing the reason I am getting the list out of range now, is because it's not parsing the file correctly?
Thanks again.
You can also use the sniffer (example taken from http://docs.python.org/library/csv.html)
csvfile = open("example.csv", "rb")
dialect = csv.Sniffer().sniff(csvfile.read(1024))
csvfile.seek(0)
reader = csv.reader(csvfile, dialect)
Yes, you'll want to use the csv module, and you'll want to set delimiter to '\t':
spamReader = csv.reader(open('spam.csv', 'rb'), delimiter='\t')
After that you should be able to iterate:
for row in spamReader:
print row[n]
This prints all rows in filename
with 'myvalue' in the fourth tab-delimited column:
with open(filename) as infile:
for row in infile:
if row.split('\t')[3] == 'myvalue':
print row
Replace 3, 'myvalue', and print
as appropriate.
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