Objects for words in a Python flashcard program

Question

I am making a flashcard program in which I take a text file that contains several columns, such as english word, french equivalent, gender, type of word, etc. My idea was to create a loop that read each line of the text file, separating by tabs, and makes an instance of a user-defined Word object for each line.

In the following block code I import the text file, process it into a list, then attempt to create an instance of a previously defined object: Word. I would like the object to have the second item on the list for it's name so that it is easily searchable, but it's not letting me do this, please can somebody help me with the code:

    file = (open('dictionary.txt', 'r')).readline()
    import re
    line_list = re.split(r'\t', file.rstrip('\n')) 

    line_list[1] = Word(line_list[0], line_list[1], line_list[2], line_list[3]) 

Answer 1

Create a dict of instances and use the second item of the lists as key. It's a bad idea to create dynamic variables.

import re
instance_dict = {}
with open('dictionary.txt') as f:
    for line in f:
        line_list = re.split(r'\t', line.rstrip('\n')) 
        instance_dict[line_list[1]] = Word(*line_list[:4]) 

---

Why the with statement?

It is good practice to use the with keyword when dealing with file objects. This has the advantage that the file is properly closed after its suite finishes, even if an exception is raised on the way.

Answer 2

You can also use the csv module:

import csv

instances = {}
with open('dictionary.txt', 'rb') as f:
    reader = csv.reader(f, delimiter='\t')
    instances = {line[1]: Word(*line) for line in reader}

Answer 3

Here's a cleaner solution using a namedtuple. You'll end up with a dict called "words" which you use to lookup each by name.

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import pprint
from collections import namedtuple

Word = namedtuple('Word', ['name', 'french', 'gender', 'type_'])

words = {}
with open('dictionary.txt', 'rU') as fin:
    for word in (Word(*r.rstrip('\n').split('\t')) for r in fin):
        words[word.name] = word

pprint.pprint(words)

Answer 4

Firstly, it's better to use with, as statements to get input from files, as the closing procedures are automatically taken care of. Secondly, to read ALL of the lines from a file, you must use readlines() rather than readline(). Try something like this :

with open('dictionary.txt','r') as file : 
    line_list = file.readlines() 
splitLineList = [] 
for lines in line_list : 
    splitLineList.append(re.split(r'\t',lines.strip('\n')) 

Answer 5

You may have an appropriate solution depending on few clarification on your requirements

"My idea was to create a loop that read each line of the text file, separating by tabs, and"

If the text file is already pre-validated or reliable to ignore error-handling (e.g. not evenly separated by single tabs).

with open('dictionary.txt', 'r') as f:
    [line.strip().split("\t") 
              for line in f.read().split("\n") 
                                  if line.strip()]

will get you the (comprehensive) list required to create Word object instances, without using re

"then attempt to create an instance of a previously defined object: Word."

with open('dictionary.txt', 'r') as f:
    [Word(line.strip().split("\t"))
              for line in f.read().split("\n") 
                                  if line.strip()]

"I would like the object to have the second item on the list for it's name so that it is easily searchable,"

Can you rewrite this with an example?

but it's not letting me do this,

  line_list[1] = Word(line_list[0], line_list[1], line_list[2], line_list[3]) 

Sorry I am loosing you here, why are using line_list[1] to refer newly created Word instances where line_list[1] itself is an argument ?

With your clarification, I would have something like this Reworked Code:

from pprint import pprint

My assumption on your Class definition:

class Word():
    def __init__(self, **kwargs):
        self.set_attrs(**kwargs)

    def __call__(self):
        return self.get_attr("swedish_word")

    def set_attrs(self, **kwargs):
        for k, v in kwargs.iteritems():
            setattr(self, k, v)

    def get_attr(self, attr):
        return getattr(self, attr)

    def get_attrs(self):
        return ({attr.upper():getattr(self, attr) for attr in self.__dict__.keys()})

    def print_attrs(self):
        pprint(self.get_attrs())


if __name__ == '__main__':

# sample entries in dictionary.txt
#    swedish_word    english_word    article           word_type
#    hund            dog              ett                noun
#    katt            cat              ett                noun
#    sova            sleep            ett                verb

    with open('dictionary.txt', 'r') as f:
        header = f.readline().strip().split("\t")


        instances = [Word(**dict(zip(header, line.strip().split("\t"))))
                              for line in f.read().split("\n")
                                                  if line.strip()]

#        for line in f.read().split("\n"):
#             data = dict(zip(header, line.strip().split("\t")))
#             w = Word(**data)

You can get instance properties for a given swedish_word like this

def print_swedish_word_properties(swedish_word):
    for instance in instances:
       if instance() == swedish_word:
           print "Properties for Swedish Word:", swedish_word
           instance.print_attrs()

print_swedish_word_properties("hund")

to have output like this

Properties for Swedish Word: hund
{'ARTICLE': 'ett',
 'ENGLISH_WORD': 'dog',
 'SWEDISH_WORD': 'hund',
 'WORD_TYPE': 'noun'}

or you can use any other class methods to search instances on various attributes