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Convert numpy array to tuple
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161
>>> arr = numpy.array(((2,2),(2,-2)))
>>> tuple(map(tuple, arr))
((2, 2), (2...
quick random row selection in Postgres
...ith OFFSET, as in
SELECT myid FROM mytable OFFSET floor(random()*N) LIMIT 1;
The N is the number of rows in mytable. You may need to first do a SELECT COUNT(*) to figure out the value of N.
Update (by Antony Hatchkins)
You must use floor here:
SELECT myid FROM mytable OFFSET floor(random()*N) L...
Regular expression for matching latitude/longitude coordinates?
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17 Answers
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how to concatenate two dictionaries to create a new one in Python? [duplicate]
...nate the items and call dict on the resulting list:
$ python -mtimeit -s'd1={1:2,3:4}; d2={5:6,7:9}; d3={10:8,13:22}' \
'd4 = dict(d1.items() + d2.items() + d3.items())'
100000 loops, best of 3: 4.93 usec per loop
Fastest: exploit the dict constructor to the hilt, then one update:
$ python -mtim...
What regular expression will match valid international phone numbers?
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\+(9[976]\d|8[987530]\d|6[987]\d|5[90]\d|42\d|3[875]\d|
2[98654321]\d|9[8543210]|8[6421]|6[6543210]|5[87654321]|
4[987654310]|3[9643210]|2[70]|7|1)\d{1,14}$
Is the correct format for matching a generic international phone number. I replaced the US land line centric international access c...
What are “named tuples” in Python?
Reading the changes in Python 3.1 , I found something... unexpected:
11 Answers
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How to trace the path in a Breadth-First Search?
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197
+50
You sho...
Maximum number of characters using keystrokes A, Ctrl+A, Ctrl+C and Ctrl+V
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14 Answers
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