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Updating MySQL primary key
...update the primary key.
alter table xx drop primary key, add primary key(k1, k2, k3);
To fix things:
create table fixit (user_2, user_1, type, timestamp, n, primary key( user_2, user_1, type) );
lock table fixit write, user_interactions u write, user_interactions write;
insert into fixit
selec...
How can I check if multiplying two numbers in Java will cause an overflow?
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14 Answers
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What is the best way to test for an empty string in Go?
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10 Answers
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Is there any way to git checkout previous branch?
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1282
From the release notes for 1.6.2
@{-1} is a way to refer to the last branch you were on. ...
R programming: How do I get Euler's number?
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150
The R expression
exp(1)
represents e, and
exp(2)
represents e^2.
This works because exp...
How to use MySQLdb with Python and Django in OSX 10.6?
This is a much discussed issue for OSX 10.6 users, but I haven't been able to find a solution that works. Here's my setup:
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How can I get the diff between all the commits that occurred between two dates with Git?
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11 Answers
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Pandas aggregate count distinct
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153
How about either of:
>>> df
date duration user_id
0 2013-04-01 30 ...
HTTP error 403 in Python 3 Web Scraping
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213
This is probably because of mod_security or some similar server security feature which blocks k...
Count cells that contain any text
...ts not empty/blank, count it. I believe this is what you want.
=COUNTIF(A1:A10, "<>")
Otherwise you can use CountA as Scott suggests
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