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Truncating floats in Python
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117
First, the function, for those who just want some copy-and-paste code:
def truncate(f, n):
...
What does .SD stand for in data.table in R
...his is your data.table:
DT = data.table(x=rep(c("a","b","c"),each=2), y=c(1,3), v=1:6)
setkey(DT, y)
DT
# x y v
# 1: a 1 1
# 2: b 1 3
# 3: c 1 5
# 4: a 3 2
# 5: b 3 4
# 6: c 3 6
Doing this may help you see what .SD is:
DT[ , .SD[ , paste(x, v, sep="", collapse="_")], by=y]
# y V1
# 1...
When is memoization automatic in GHC Haskell?
I can't figure out why m1 is apparently memoized while m2 is not in the following:
4 Answers
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What is IP address '::1'?
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152
::1 is the loopback address in IPv6. Think of it as the IPv6 version of 127.0.0.1.
See http:...
SQL Server dynamic PIVOT query?
...me,
category varchar(3),
amount money
)
insert into temp values ('1/1/2012', 'ABC', 1000.00)
insert into temp values ('2/1/2012', 'DEF', 500.00)
insert into temp values ('2/1/2012', 'GHI', 800.00)
insert into temp values ('2/10/2012', 'DEF', 700.00)
insert into temp values ('3/1/2012', 'ABC...
Sql Server equivalent of a COUNTIF aggregate function
...ondition (e.g. count only records where a certain column value is equal to 1).
9 Answers
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What belongs in an educational tool to demonstrate the unwarranted assumptions people make in C/C++?
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91
The order of evaluation of subexpressions, including
the arguments of a function call and
oper...
Delete element in a slice
...d i is the index of the element you want to delete:
a = append(a[:i], a[i+1:]...)
... is syntax for variadic arguments in Go.
Basically, when defining a function it puts all the arguments that you pass into one slice of that type. By doing that, you can pass as many arguments as you want (for ex...
How do you create a yes/no boolean field in SQL server?
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11 Answers
11
Active
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How to pass a single object[] to a params object[]
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100
A simple typecast will ensure the compiler knows what you mean in this case.
Foo((object)new ...