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Possible Duplicate:
Good Primer for Python Slice Notation 

hxs = HtmlXPathSelector(response)
sites = hxs.select('//table/tr')[1:]

Here i understand that scrape from second row. But i was not able to find any links to understand advanced topics on that "[1:]". Please share me any reference links

Community
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Joshua
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    It's called "slicing". See here: http://stackoverflow.com/questions/509211/good-primer-for-python-slice-notation – Peter Jul 18 '12 at 06:58

1 Answers1

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It is used to extract slices from arrays/lists.

It can be used [start:end[:ratio]]

ration is optional, and it is the jump -- ratio=2 means to extract even indexes.

if end is negative, start to count from the end of the list that number.

[1,2,3,4][1:-1:2]

means

[2]
alinsoar
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