I have an file with a specific data I would like to pull.
The file looks like this:
DS User ID 1
random garbage
random garbage
DS N user name 1
random garbage
DS User ID 2
random garbage
random garbage
DS N user 开发者_JAVA百科name 2
So far I have:
import sys
import re
f = open(sys.argv[1])
strToSearch = ""
for line in f:
strToSearch += line
patFinder1 = re.compile('DS\s+\d{4}|DS\s{2}\w\s{2}\w.*|DS\s{2}N', re.MULTILINE)
for i in findPat1:
print(i)
My output to screen looks like this:
DS user ID 1
DS N user name 1
DS user ID 2
DS N user name 2
If I write to file using:
outfile = "test.dat"
FILE = open(outfile,"a")
FILE.writelines(line)
FILE.close()
Everything is pushed to a single line:
DS user ID 1DS N user name 1DS user ID 2DS N user name 2
I can live with the first scenario for the ouput. Ideally though I would like to strip the 'DS' and 'DS N' from the output file and have it comma separated.
User ID 1,user name 1
User ID 2, username 2
Any ideas on how to get this accomplished?
It's difficult to provide a robust solution without understanding the actual input data format, how much flexibility is allowed, and how the parsed data is going to be used.
From just the sample input/output given above, one can quickly cook up a working sample code:
out = open("test.dat", "a") # output file
for line in open("input.dat"):
if line[:3] != "DS ": continue # skip "random garbage"
keys = line.split()[1:] # split, remove "DS"
if keys[0] != "N": # found ID, print with comma
out.write(" ".join(keys) + ",")
else: # found name, print and end line
out.write(" ".join(keys[1:]) + "\n")
Output file will be:
User ID 1,user name 1
User ID 2,user name 2
This code can of course be made much more robust using regex if the format specification is known. For example:
import re
pat_id = re.compile(r"DS\s+(User ID\s+\d+)")
pat_name = re.compile(r"DS\s+N\s+(.+\s+\d+)")
out = open("test.dat", "a")
for line in open("input.dat"):
match = pat_id.match(line)
if match: # found ID, print with comma
out.write(match.group(1) + ",")
continue
match = pat_name.match(line)
if match: # found name, print and end line
out.write(match.group(1) + "\n")
Both the examples above assumes that "User ID X" always comes before "N user name X", hence the respective trailing chars of "," and "\n".
If the order is not specific, one can store the values in a dictionary using the numeric ID as a key then print out the ID/name pair after all input has been parsed.
If you provide more info, perhaps we can be of more help.
print
adds a newline character after the arguments, but writelines
does not. So you have to write like:
file = open(outfile, "a")
file.writelines((i + '\n' for i in findPat1))
file.close()
The writelines
statement can also be written as:
for i in findPat1:
file.write(i + '\n')
FILE.writelines(line)
does not add line separators.
Just do:
FILE.write(line + "\n")
Or:
FILE.write("\n".join(lines))
import re
ch ='''\
DS User ID 1
random garbage
random garbage
DS N user name 1
random garbage
DS User ID 2
random garbage
random garbage
DS N user name 2'''
RE = '^DS (User ID (\d+)).+?^DS N( user name \\2)'
with open('outputfile.txt','w') as f:
for match in re.finditer(RE,ch,re.MULTILINE|re.DOTALL):
f.write(','.join(match.groups())+'\n')
EDIT:
replaced
RE = '^DS (User ID \d+).+?^DS N( user name \d+)'
with
RE = '^DS (User ID (\d+)).+?^DS N( user name \\2)'
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