added csv_split
This commit is contained in:
Michael Herman
parent
8b65a7c03d
commit
9828e28fc5
234
12_csv_split.py
234
12_csv_split.py
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### WIP
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import sys
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import os
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import getopt
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import csv
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import argparse
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"""
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Splits a CSV file into multiple pieces based on command line arguments.
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Splits a CSV file into multiple pieces based on command line arguments.
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Arguments:
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`-h`: help file of usage of the script
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`-i`: input file name
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`-o`: output file, A %s-style template for the numbered output files.
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`-o`: output file name
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`-r`: row limit to split
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`-c`: A %s-style template for the numbered output files.
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Default settings:
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`output_path` is the current directory
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`keep_headers` is on (headers will be kept)
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`delimeter` is ,
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headers are displayed on each split file
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the default delimeter is a comma
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Example usage:
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# split by every 10000 rows
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>> python 12_csv_split.py -i input.csv -o rownumber -r 10000
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# split by unique items in column 0
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>> python 12_csv_split.py -i input.csv -o userid -c 0
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# access help
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>> python 12_csv_split.py -h for help
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```
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# split csv by every 100 rows
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>> python csv_split.py -i input.csv -o output -r 100
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```
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"""
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def main(argv):
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argument_dict = grab_command_line_arguments(argv)
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parse_file(argument_dict)
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def get_arguments():
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"""Grab user supplied arguments using the argparse library."""
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# Use arparse to get command line arguments
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parser = argparse.ArgumentParser()
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parser.add_argument("-i", "--input_file", required=True,
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help="csv input file (with extension)", type=str)
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parser.add_argument("-o", "--output_file", required=True,
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help="csv output file (without extension)", type=str)
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parser.add_argument("-r", "--row_limit", required=True,
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help="row limit to split csv at", type=int)
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args = parser.parse_args()
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# Check if the input_file exits
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is_valid_file(parser, args.input_file)
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# Check if the input_file is valid
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is_valid_csv(parser, args.input_file, args.row_limit)
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return args.input_file, args.output_file, args.row_limit
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def grab_command_line_arguments(argv):
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# global variables
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inputfile = ''
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outputfile = ''
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rowlimit = ''
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columnindex = ''
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argument_dict = {}
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# grab arguments
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opts, args = getopt.getopt(argv,"hi:o:r:c:",["ifile=","ofile=","rowlimit=","columnindex="])
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# end if no arguments provided
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if not opts:
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print "No options provided. Try again. Use `-h` for help."
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sys.exit()
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# grab arguments
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for opt, arg in opts:
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if opt == '-h':
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print 'csvsplit.py -i <inputfile> -r <row limit> -c <column index> -o <outputfile>'
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sys.exit()
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elif opt in ("-i", "--ifile"):
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inputfile = arg
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elif opt in ("-o", "--ofile"):
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outputfile = arg
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elif opt in ("-r", "--rowlimit"):
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rowlimit = arg
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elif opt in ("-c", "--columnindex"):
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columnindex = arg
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# Output arguments
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print "\nArguments:"
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if inputfile:
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argument_dict["input_file"] = inputfile
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print "Input file is '{}'".format(inputfile)
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else:
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"Please enter an input file."
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if outputfile:
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argument_dict["output_file"] = outputfile
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print "Output file is '{}'".format(outputfile)
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else:
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print "Please enter an output file."
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if rowlimit:
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argument_dict["rowlimit"] = rowlimit
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print "Rowlimit is '{}'".format(rowlimit)
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if columnindex:
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argument_dict["columnindex"] = columnindex
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print "Columnindex is '{}'".format(columnindex)
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if rowlimit and columnindex:
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print "Please use either a rowlimit or columnlimit, not both."
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sys.exit()
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if not rowlimit or columnindex:
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print "Please enter either a rowlimit or columnlimit."
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sys.exit()
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# to do - check to make sure file, rowlimit, and columnlimit exist
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print argument_dict
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return argument_dict
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def is_valid_file(parser, file_name):
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"""Ensure that the input_file exists."""
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if not os.path.exists(file_name):
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parser.error("The file '{}' does not exist!".format(file_name))
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sys.exit(1)
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def parse_file(argument_dict):
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#split csv file by certain rownumber
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if argument_dict["rowlimit"]:
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rowlimit = int(argument_dict["rowlimit"])
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output_name_file = "{}.csv".format(argument_dict["output_file"])
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output_path='.'
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keep_headers=True
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delimiter=','
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filehandler = open(argument_dict["input_file"],'r')
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reader = csv.reader(filehandler, delimiter=delimiter)
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current_piece = 1
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current_out_path = os.path.join(
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output_path,
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output_name_file
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def is_valid_csv(parser, file_name, row_limit):
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"""
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Ensure that the # of rows in the input_file
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is greater than the row_limit.
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"""
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row_count = 0
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for row in csv.reader(open(file_name)):
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row_count += 1
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# Note: You could also use a generator expression
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# and the sum() function to count the rows:
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# row_count = sum(1 for row in csv.reader(open(file_name)))
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if row_limit > row_count:
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parser.error(
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"The 'row_count' of '{}' is > the number of rows in '{}'!"
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.format(row_limit, file_name)
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)
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current_out_writer = csv.writer(open(current_out_path, 'w'), delimiter=delimiter)
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current_limit = rowlimit
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if keep_headers:
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headers = reader.next()
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current_out_writer.writerow(headers)
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for i, row in enumerate(reader):
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if i + 1 > current_limit:
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current_piece += 1
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current_limit = rowlimit * current_piece
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current_out_path = os.path.join(
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sys.exit(1)
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def parse_file(arguments):
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"""
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Splits the CSV into multiple files or chunks based on the row_limit.
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Then create new CSV files.
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"""
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input_file = arguments[0]
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output_file = arguments[1]
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row_limit = arguments[2]
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output_path = '.' # Current directory
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# Read CSV, split into list of lists
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with open(input_file, 'r') as input_csv:
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datareader = csv.reader(input_csv)
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all_rows = []
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for row in datareader:
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all_rows.append(row)
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# Remove header
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header = all_rows.pop(0)
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# Split list of list into chunks
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current_chunk = 0
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for i in range(0, len(all_rows), row_limit): # Loop through list
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chunk = all_rows[i:i + row_limit] # Create single chunk
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current_output = os.path.join( # Create new output file
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output_path,
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output_name_file
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"{}-{}.csv".format(output_file, current_chunk)
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)
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current_out_writer = csv.writer(open(current_out_path, 'w'), delimiter=delimiter)
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# elif columnindex: #split csv file accrording to unique values of certain column,it's like filter only certain item in excel
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# itemlist = []
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# columnindex = int(columnindex)
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# output_name_template= outputfile+'_%s.csv'
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# output_path='.'
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# keep_headers=True
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# delimiter=','
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# filehandler = open(inputfile,'r')
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# reader = csv.reader(filehandler, delimiter=delimiter)
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# if keep_headers:
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# headers = reader.next()
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# Add header
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chunk.insert(0, header)
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# for i, row in enumerate(reader):
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# Write chunk to output file
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with open(current_output, 'w') as output_csv:
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writer = csv.writer(output_csv)
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writer = writer.writerows(chunk)
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# current_out_path = os.path.join(
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# output_path,
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# output_name_template % row[columnindex] )
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# if row[columnindex] not in itemlist:
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# try:
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# current_out_writer = csv.writer(open(current_out_path, 'w'), delimiter=delimiter)
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# except IOError:
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# continue
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# else:
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# itemlist.append(row[columnindex])
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# if keep_headers:
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# current_out_writer.writerow(headers)
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# current_out_writer.writerow(row)
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# else:
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# current_out_writer = csv.writer(open(current_out_path, 'a'), delimiter=delimiter)
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# current_out_writer.writerow(row)
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# print 'totally %i unique items in column %i \n' % (len(itemlist),columnindex)
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# else:
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# print "oops, please check instruction of script by >>./csvsplit.py -h"
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# Output info
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print ""
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print "Chunk # {}:".format(current_chunk)
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print "Filepath: {}".format(current_output)
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print "# of rows: {}".format(len(chunk))
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# Create new chunk
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current_chunk += 1
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if __name__ == "__main__":
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main(sys.argv[1:])
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arguments = get_arguments()
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parse_file(arguments)
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