Python converting UUID's from string

Question

I have a text file that includes UUIDS that all look like this:

A4AB4CD2-016B-411E-8BA1-0000C592BF17

When I try and parse/print the file with python, most (but not all) end up looking like this:

12:40:54:457

There are three chunks per line that I'm parsing, a double, a date, and this uuid. The first two parts work fine. The relevant lines of code are:

for line in fileLines:

    parts = line.split()
    # Parse first two chunks
    outputFile.write(""" WHERE tableID = '""" + uuid.UUID(parts[2]) + """'""")

This fails because the UUIDs are already of the form 12:40:54:547, but I don't know what this sub-type of UUID is called, let alone how to appropriately parse it. My goal is simply to read in the uuid exactly as it is, and re-print it with some extra text around it so I can run it as an SQL script.

I'm running python 3.3.2

A full line of input looks like this:

339.00  2013-06-18 12:40:54.457 A4AB4CD2-016B-411E-8BA1-0000C592BF17

Looks like your line.split() splits in a datetime. Do you have a full input line for us. — RickyA
– RickyA, Commented Oct 20, 2014 at 15:35
On a related matter, it looks like you're generating SQL by concatenating strings containing user input. Don't do that. — Max Noel
– Max Noel, Commented Oct 20, 2014 at 15:37
Now that you've shown a line of input, the problem is obvious. You have two date/time fields, so the UUID is in parts[3]. — Mark Ransom
– Mark Ransom, Commented Oct 20, 2014 at 15:38
Silly maybe, but don't sweat over it too much. We all have blind spots and/or bad days. — Mark Ransom
– Mark Ransom, Commented Oct 20, 2014 at 15:40

Parker · Accepted Answer · 2014-10-20 15:41:36Z

3

If the UUID will always be last in the line, access it with [-1]

outputFile.write(""" WHERE tableID = '""" + uuid.UUID(parts[-1]) + """'""")

In the example you give parts[2] will always return the time. If your lines are consistent, you can use parts[2], but if the data up to the UUID varies, just always pick the last element after the split

answered Oct 20, 2014 at 15:41

Parker

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3 Comments

Vinz Over a year ago

more precisely, parts[0] is 339.00, parts[1] is the date, parts[2] is the time and the uuid is parts[3]

dckuehn Over a year ago

Yep, thanks. I guess I was thinking to fast that double, datetime, and uuid would necessarily equal 3 parts. Also, I didn't know you can access the last element with [-1]. So thanks for that tidbit as well.

Parker Over a year ago

Sure thing, it may be worth noting that you can also use [-2] to get the second to last element, [-3] to get the third last, etc

Bala · Accepted Answer · 2014-10-20 16:18:15Z

-1

string.split() is a magic , you wont need to specify your delimiter it will split.

part = "339.00 2013-06-18 12:40:54.457 A4AB4CD2-016B-411E-8BA1-0000C592BF17"

part.split() ; part.split(" ") # does the same.

['339.00', '2013-06-18', '12:40:54.457', 'A4AB4CD2-016B-411E-8BA1-0000C592BF17']

['339.00', '', '2013-06-18', '12:40:54.457', 'A4AB4CD2-016B-411E-8BA1-0000C592BF17']

My opinion is use str(part.split()[-1]).

Regarding UUID use string conversion while converting into UUID see below for your reference. ( or it may cause issue )

uuid.UUID("A4AB4CD2-016B-411E-8BA1-0000C592BF17")

UUID('a4ab4cd2-016b-411e-8ba1-0000c592bf17')

str(uuid.UUID("A4AB4CD2-016B-411E-8BA1-0000C592BF17"))

'a4ab4cd2-016b-411e-8ba1-0000c592bf17'

So it can be like this.

for line in fileLines:

parts = line.split()

# Parse first two chunks

outputFile.write(""" WHERE tableID = '""" + str(uuid.UUID(parts[-1])) + """'""")

answered Oct 20, 2014 at 16:18

Bala

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1 Comment

dckuehn Over a year ago

Thanks for your response, but I was already using str.split() with no argument to split on whitespace. I also ended up not needing uuid.UUID() at all because that was not the issue. I was in fact trying to parse the second half of the date-time object as the uuid.

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