file_writer_csv.py

import os
import glob
 
 
class Directory(object):
    """Creates wrapper object for a directory.
 
    Attributes:
        path: str, relative path to directory.
    """
 
    def __init__(self, path = '.'):
        """Creates wrapper class for a valid directory.
 
        Args:
            path: Path to directory. Defaults to current directory.
        Returns:
            None
        Raises:
            Exception: If directory path is invalid.
        """
        if not os.path.isdir(path):
            raise Exception("Invalid directory path.")
        self.path = os.path.normpath(path)
    
    def file_names(self):
        """List names of files (excludes directories).
 
        Returns:
            Sorted (ascending) array of file names
        """
        all_items = glob.glob(self.path + '/*')
        files_only = [os.path.basename(f) for f in all_items if os.path.isfile(f)] 
        files_only.sort()
        return files_only

    def directory_names(self):
        all_items = glob.glob(self.path + '/*')
        directories_only = [os.path.basename(f) for f in all_items if os.path.isdir(f)]
        directories_only.sort()
        return directories_only 
 
 
class File(object):
    """Creates wrapper object for a file.
 
    Attributes:
        path: str, relative path to file.
    """ 
 
    def __init__(self, path):
        """Creates wrapper class for a valid file.
 
        Args:
            path: Path to file.
        Returns:
            None
        Raises:
            Exception: If file path is invalid.
        """ 
        if not os.path.isfile(path): # check isfile during runtime?
            raise Exception("Invalid file path.")
        self.path = path
 
    def read(self):
        """Reads content of file.
 
        Returns:
            String of file data.
        """
        f = open(self.path, 'r')
        content = f.read()
        f.close()
        return content
 
    def write(self, data):
        f = open(self.path, 'w')
        f.writelines(data)
        f.close()
 
    def append_to_line(self, line_num, chars):
        """Writes content to the end of a specified line in the file.
 
        Args:
            line_num: int, line number in file (first line is 0).
            chars: str appended to line.
        Returns:
            None
        Raises:
            IndexError: If line_num is out of file range.
        """
        f = open(self.path, 'r')
        data = f.readlines()
        try:
            data[line_num] = data[line_num].rstrip('\n') + chars + '\n'
        except IndexError:
            raise IndexError("Line number is out of range.")
        finally:
            f.close()
        f.close()
        self.write(data)
 
 
class CSVFile(File):
  
    def parse(self):
        data = self.read()
        data = [line.split(',') for line in data.split('\n')]
        if data[-1] == ['']:
            data.pop()
        return data
  
    def get_cell(self, row, col):
        return self.parse()[row][col]
  
    def write_cell(self, row, col, data):
        csv = self.parse()
        csv[row][col] = str(data)
        string = '\n'.join([','.join(row) for row in csv])
        self.write(string)
 
 
def get_timestamps(directory):
    return [file_name[7:13] for file_name in directory.file_names()]

## MAIN METHOD
if __name__ == "__main__":
    timestamp_root = "1824/"
    root_directory = Directory(timestamp_root)
    timestamp_directories =  root_directory.directory_names()
    current_timestamp_directory = Directory(timestamp_root + timestamp_directories[0])
    timestamps = get_timestamps(current_timestamp_directory)
    
    f = CSVFile('1824.csv')
    print f.parse()[0]
 
    for i in range(1, len(f.parse())):
        if len(timestamps) == 0:
            print "Moving to new directory..."
            timestamp_directories.pop(0)
            timestamps = get_timestamps(Directory(timestamp_root + timestamp_directories[0]))
        f.write_cell(i, 16, timestamps[0])
        print "Wrote " + str(timestamps[0]) + " to row "  + str(i + 1)
        if f.parse()[i][15] == 'w':
            timestamps.pop(0)        
            print 'check on row', i
    print "done"