On Sat, Dec 17, 2016 at 1:10 PM, John <miao...@gmail.com> wrote: > > Hi, > > I am new to Python, and I believe it's an easy question. I know R and > Matlab. > > ************ > >>> x=[1,2,3,4,5,6,7] > >>> x[0] > 1 > >>> x[1:5] > [2, 3, 4, 5] > ************* > > My question is: what does x[1:5] mean? By Python's convention, the first > element of a list is indexed as "0". Doesn't x[1:5] mean a sub-list of x, > indexed 1,2,3,4,5? If I am right, it should print [2,3,4,5,6]. Why does it > print only [2,3,4,5]? >
What you are asking about is "slicing". x[1:5] returns everything between index 1 through, but NOT including, index 5. See https://docs.python.org/3/tutorial/introduction.html#strings which will give examples using strings. A bit later the tutorial addresses slicing in a list context. BTW, the Python Tutorial is well worth reading in full! -- boB -- https://mail.python.org/mailman/listinfo/python-list
