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copied!<p><a href="http://docs.python.org/library/string.html" rel="noreferrer">string.join</a> doesn't do what you think. join is used to combine a list of words into a single string with the given seperator. Ie:</p> <pre><code>>>> ",".join(('foo', 'bar', 'baz')) 'foo,bar,baz' </code></pre> <p>The code snippet you posted will attempt to insert myString between every character in the variable line. You can see how that will get big quickly :-). Are you trying to read the entire file into a single string, myString? If so, the way you want to concatenate the strings is like this:</p> <pre><code>myString = myString + line </code></pre> <p>While I'm here... since you're learning Python here are some other suggestions.</p> <p>There are easier ways to read an entire file into a variable. For instance:</p> <pre><code>fileIN = open("testdata.txt", "r") myString = fileIN.read() </code></pre> <p>(This won't have the exact behaviour of your existing strip() code, but may in fact do what you want.)</p> <p>Also, I would never recommend practical Python code use recursion to iterate over a string. Your code will make a function call (and a stack entry) for every character in the string. Also I'm not sure Python will be very smart about all the uses of bigString[1:]: it may well create a second string in memory that's a copy of the original without the first character. The simplest way to process every character in a string is:</p> <pre><code>for mychar in bigString: ... do your stuff ... </code></pre> <p>Finally, you are using the list named "checked" to see if you've ever seen a particular character before. But the membership test on lists ("if myChar in checked") is slow. In Python you're better off using a dictionary:</p> <pre><code>checked = {} ... if not checked.has_key(myChar): checked[myChar] = True ... </code></pre> <p>This exercise you're doing is a great way to learn several Python idioms.</p>

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