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Guards vs. if-then-else vs. cases in Haskell
...and guards should almost always be used instead.
let absOfN =
if n < 0 -- Single binary expression
then -n
else n
Every if..then..else expression can be replaced by a guard if it is at the top level of a function, and this should generally be preferred, since you can add more cases more...
Java regular expression OR operator
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edited Jan 9 '10 at 0:57
answered Jan 9 '10 at 0:46
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How to change column datatype from character to numeric in PostgreSQL 8.4
...nding on your data):
alter table presales alter column code type numeric(10,0) using code::numeric;
-- Or if you prefer standard casting...
alter table presales alter column code type numeric(10,0) using cast(code as numeric);
This will fail if you have anything in code that cannot be cast to num...
How do I rename all files to lowercase?
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answered Oct 16 '11 at 20:39
wjlwjl
6,29011 gold badge2828 silver badges4646 bronze badges
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How do I break out of a loop in Scala?
...f loops.
Suppose you want to sum numbers until the total is greater than 1000. You try
var sum = 0
for (i <- 0 to 1000) sum += i
except you want to stop when (sum > 1000).
What to do? There are several options.
(1a) Use some construct that includes a conditional that you test.
var sum...
How are cookies passed in the HTTP protocol?
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302
The server sends the following in its response header to set a cookie field.
Set-Cookie:name=v...
Pip freeze vs. pip list
...ecific format for pip to understand, which is
feedparser==5.1.3
wsgiref==0.1.2
django==1.4.2
...
That is the "requirements format".
Here, django==1.4.2 implies install django version 1.4.2 (even though the latest is 1.6.x).
If you do not specify ==1.4.2, the latest version available would be in...
Alter MySQL table to add comments on columns
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answered Jan 29 '10 at 14:18
RufinusRufinus
23.5k66 gold badges5959 silver badges7878 bronze badges
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Test whether string is a valid integer
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[[ $var =~ ^-?[0-9]+$ ]]
The ^ indicates the beginning of the input pattern
The - is a literal "-"
The ? means "0 or 1 of the preceding (-)"
The + means "1 or more of the preceding ([0-9])"
The $ indicates the end of the input pattern
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How to make gradient background in android
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answered Dec 18 '12 at 10:11
Gunnar KarlssonGunnar Karlsson
27.6k1010 gold badges6464 silver badges6969 bronze badges
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