title: Python3 Memory Error while modifying large dataset
body: <p>I am trying to implement symspell in python3 (64 bit) and I have a txt file that is 20 MB which includes words with frequencies. I can successfully load this data to a dictionary named <code>originalDictionary</code> . As a next step for every word in the dictionary I should delete one char at a time and also add that modified word to another dictionary called <code>editDictionary</code>. But I got a memory error. 
  I am running this on Windows10(x64) with 16gb RAM.
  What can i do to tackle this problem? </p>
  
  <pre><code> for word in originalDictionary:
      for i in range(len(word)):
          edit1 = word[0:i] + word[i + 1:]
          if edit1 not in editedDictionary:
              editedDictionary[edit1] = [word]
          else:
              editedDictionary[edit1].append(word)
  </code></pre>
  
  <p>Below is error:</p>
  
  <pre><code>    Traceback (most recent call last):
    File "C:\Program Files\JetBrains\PyCharm 2018.3.2\helpers\pydev\pydevd.py", line 1741, in &lt;module&gt;
      main()
    File "C:\Program Files\JetBrains\PyCharm 2018.3.2\helpers\pydev\pydevd.py", line 1735, in main
      globals = debugger.run(setup['file'], None, None, is_module)
    File "C:\Program Files\JetBrains\PyCharm 2018.3.2\helpers\pydev\pydevd.py", line 1135, in run
      pydev_imports.execfile(file, globals, locals)  # execute the script
    File "C:\Program Files\JetBrains\PyCharm 2018.3.2\helpers\pydev\_pydev_imps\_pydev_execfile.py", line 18, in execfile
      exec(compile(contents+"\n", file, 'exec'), glob, loc)
    File "C:/Users/ee/PycharmProjects/SymSpell/spellCorrector.py", line 98, in &lt;module&gt;
      createDictionaries()
    File "C:/Users/ee/PycharmProjects/SymSpell/spellCorrector.py", line 40, in createDictionaries
      editedDictionary[edit1] = [word]
  MemoryError
  </code></pre>