CODEWITHSUNDEEP
pythonstringparsingtextindexing
Meh
Meh

Reputation: 607

Return the file extension from filename using string index in python

I am having a bit of trouble putting this logic on paper:

The string I would like to parse: "Jan - 2012 Presentation v1.3.ppt.pdf - 500KB" This string can vary but the structure is always "NAME+EXT+FILESIZE"

I want to return the extension. However for obvious reasons I cannot just split(".") So I came up with something else:

stringy = "Jan - 2012 Presentation v1.3.ppt.pdf - 500KB"
ext = [".pdf",".jpg",".ppt",".txt",".doc"]

for i in ext:
    indx = stringy.find(i)
    ...

I got stuck where I need to figure out how to tell Python to take the extension starting with the biggest index yielded. Should be something like whatiwant = stringy[indx:4], but I can't figure out how to tell it to only take the largest index... The largest index will obviously mean the last extension in the string, which is the one I want to get. In this particular example, I don't care about "ppt", but rather the "pdf".

Can this perhaps be done in a more pythonic way? Or at least more efficiently?

Upvotes: 1

Views: 983

Answers (3)

Ashwini Chaudhary
Ashwini Chaudhary

Reputation: 250891

using regex:

>>> strs="Jan - 2012 Presentation v1.3.ppt.pdf - 500KB"

>>> re.findall(r"(\.\w+)",strs)[-1]
'.pdf'

or:

>>> re.findall(r".*(\.\w+)",strs)
['.pdf']

Upvotes: 1

avasal
avasal

Reputation: 14854

In [44]: stringy[stringy.rfind('.'):stringy.rfind('.')+4]
Out[44]: '.pdf'

Upvotes: 2

jvallver
jvallver

Reputation: 2340

Try this:

>>> stringy = "Jan - 2012 Presentation v1.3.ppt.pdf - 500KB"
>>> extension = stringy.split(".")[-1].split("-")[0].strip()
>>> extension
'pdf'

Upvotes: 0

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