import sys
import os
OUTFIL_PREFIX = "out_"
def make_out_filename(prefix, idx):
'''Make a filename with a serial number suffix.'''
return prefix + str(idx).zfill(4)
def split(in_filename, lines_per_file):
'''Split the input file in_filename into output files of
lines_per_file lines each. Last file may have less lines.'''
in_fil = open(in_filename, "r")
outfil_idx = 1
out_filename = make_out_filename(OUTFIL_PREFIX, outfil_idx)
out_fil = open(out_filename, "w")
# Using chain assignment feature of Python.
line_count = tot_line_count = file_count = 0
# Loop over the input and split it into multiple files.
# A text file is an iterable sequence, from Python 2.2,
# so the for line below works.
for lin in in_fil:
# Bump vars; change to next output file.
if line_count >= lines_per_file:
tot_line_count += line_count
line_count = 0
file_count += 1
out_fil.close()
outfil_idx += 1
out_filename = make_out_filename(OUTFIL_PREFIX, outfil_idx)
out_fil = open(out_filename, "w")
line_count += 1
out_fil.write(lin)
in_fil.close()
out_fil.close()
sys.stderr.write("Output is in file(s) with prefix {}\n".format(OUTFIL_PREFIX))
def usage():
sys.stderr.write(
"Usage: {} in_filename lines_per_file\n".format(sys.argv[0]))
def main():
if len(sys.argv) != 3:
usage()
sys.exit(1)
try:
# Get and validate in_filename.
in_filename = sys.argv[1]
# If input file does not exist, exit.
if not os.path.exists(in_filename):
sys.stderr.write("Error: Input file '{}' not found.\n".format(in_filename))
sys.exit(1)
# If input is empty, exit.
if os.path.getsize(in_filename) == 0:
sys.stderr.write("Error: Input file '{}' has no data.\n".format(in_filename))
sys.exit(1)
# Get and validate lines_per_file.
lines_per_file = int(sys.argv[2])
if lines_per_file <= 0:
sys.stderr.write("Error: lines_per_file cannot be less than or equal to 0.\n")
sys.exit(1)
# If all checks pass, split the file.
split(in_filename, lines_per_file)
except ValueError as ve:
sys.stderr.write("Caught ValueError: {}\n".format(repr(ve)))
except IOError as ioe:
sys.stderr.write("Caught IOError: {}\n".format(repr(ioe)))
except Exception as e:
sys.stderr.write("Caught Exception: {}\n".format(repr(e)))
raise
if __name__ == '__main__':
main()
