why [::-1] reverse a list instead of returning the first index only? : <p>peace upon you guys
i was starting to learn python using head first book and i came across this 
[::-1] in lists i know that when u dont include the "start" it equals to 0 by default and the "stop" equals the maximum index number in the list 
so if we said the max is 5 so this means [0:5:-1] and if u run this u will get the first index but if u run this [::-1] it gives u the list in reverse order why?
isnt [::-1] == [0:5:-1] but it seems it equals this instead [-1:5:-1]!
so why the step index here define the start index !?   </p>

<pre><code>book = "The Hitchhiker's Guide to the Galaxy"
booklist = list(book)
booklist = ['T', 'h', 'e', ' ', 'H', 'i', 't', 'c', 'h', 'h', 'i',
        'k', 'e', 'r', "'", 's', ' ', 'G', 'u', 'i', 'd', 'e',
        ' ', 't', 'o', ' ', 't', 'h', 'e', ' ', 'G', 'a', 'l',
        'a', 'x', 'y']
backwards = booklist[::-1]
print(''.join(backwards))
</code></pre>

<p>output >>> yxalaG eht ot ediuG s'rekihhctiH ehT  </p>

<p><code>backwards = booklist[0::-1]
 print(''.join(backwards))</code></p>

<p>output >>> T</p>

<pre><code>backwards = booklist[-1::-1]
print(''.join(backwards))
</code></pre>

<p>output >>> yxalaG eht ot ediuG s'rekihhctiH ehT</p>
