python - for loop only returning the last word in a list of many words

Question

for word in wordStr:
    word = word.strip()
print word

When the above code analyzes a .txt with thousands of words, why does it only return the last word in the .txt file? What do I need to do to get it to return all the words in the text file?

Answer 1

Because you're overwriting word in the loop, not really a good idea. You can try something like:

wordlist = ""
for word in wordStr:
    wordlist = "%s %s"%(wordlist,word.strip())
print wordlist[1:]

This is fairly primitive Python and I'm sure there's a more Pythonic way to do it with list comprehensions and all that new-fangled stuff :-) but I usually prefer readability where possible.

What this does is to maintain a list of the words in a separate string and then add each stripped word to the end of that list. The [1:] at the end is simply to get rid of the initial space that was added when the first word was tacked on to the end of the empty word list.

It will suffer eventually as the word count becomes substantial since tacking things on to the end of a string is less optimal than other data structures. However, even up to 10,000 words (with the print removed), it's still well under a second of execution time.

At 50,000 words it becomes noticeable, taking 3 seconds on my box. If you're going to be processing that sort of quantity, you would probably opt for a real list-based solution like (equivalent to above but with a different underlying data structure):

wordlist = []
for word in wordStr:
    wordlist.append (word.strip())
print wordlist

That takes about 0.22 seconds (without the print) to do my entire dictionary file, some 110,000 words.