Question

Program Language: PYTHON

Consider the following file structure: each line of the file contains a word. The words are in sorted order. For example, a file might look like this

apple
apple
apple
apple
banana
bargain
brick
brick
sample
sample
simple
text
text
text

Write a program that asks the user for a filename with this structure. The program's job is to write the sequence of words to another file, without any duplicates. Name the output file  result.txt. Each word is on its own line. Using the input file example above, result.txt would contain the following lines:
apple
banana
bargain
brick
sample
simple
text

Do not store the words in any type of data structure, such as a list (we learn those later) or a set. Your program has to determine if it writes a word to the output file or not as is reads in the data.

HINT: Consider someone hands you a deck of cards; the deck is face down. You are told that the cards are sorted. You don't know if it is a full deck though - some cards may be missing. You can only turn over the cards one at a time; you may hold at most two cards at a time. Your job is to create a pile where there are no duplicates and discard the rest. How would you do it? Once you've done this by hand, consider what information you needed and the logic you used, then write the code to replicate that algorithm.

Here are 2 files to test your program. You can also make your own text file for testing. Your solution should work with any file that matches the described format.

• data.txtLinks to an external site.
• otherData.txtLinks to an external site.

If the program cannot find your file, it will crash and raise an error to the user (those red messages). If you want to experiment, use a try/except block to display an error message to the user and then ask for a new filename (see section 6.4). This is not a requirement for the lab.

The only file you have to sumbit is the .py file. I don't need the text files.

data.txt

apple
apple
apple
apple
banana
brick
brick
sample
sample
text
text
text

otherData.txt

a
b
c
c
c
c
c
c
d
d
d
d
d
d
d
d
f
f
f
f
f
f
f
f
f
f
f
g

Answer 1

'''
Python version : 2.7
Python program to read words from a file containing one word per line and
output the words to another file such that duplicate words from input file
are not copied to output file
'''

def main():
   # input of input filename  
   inFilename = raw_input('Enter input filename : ')
   # open input and output file
   inFile = open(inFilename)
   outFile = open("result.txt","w")
   # read a word from file
   word = inFile.readline()
   previousWord = "" # variable to store the last word read
   # loop continues till the end of file
   while word:
       # if previous read word is not the same as current read word
       if previousWord != word.strip():
           # update previousWord, strip is used to remove whitespaces from word
           previousWord = word.strip()
           outFile.write(word) # output the word to output file
       word = inFile.readline() # read next word from input file
  
   # check that the last word read was not the same as previousWord
   if previousWord != word:
       # if not same output the word to output file
       outFile.write(word.strip())
   # close both the files  
   outFile.close()
   inFile.close()

#call the main function  
main()  
#end of program

Code Screenshot:

Output:

Input file 1:

Output file 1:

Input file 2:

Output file 2: