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How is this fibonacci-function memoized?
...cases where we don't want it to do that for us automatically.
(edit:) Consider these re-writes:
fib1 = f fib2 n = f n fib3 n = f n
where where where
f i = xs !! i f i = xs ...
git rebase, keeping track of 'local' and 'remote'
... when resolving conflicts. I sometimes have the impression that they swap sides from one commit to the next.
4 Answers
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Why can't I initialize non-const static member or static array in class?
...ws only static constant integral or enumeration types to be initialized inside the class. This is the reason a is allowed to be initialized while others are not.
Reference:
C++03 9.4.2 Static data members
§4
If a static data member is of const integral or const enumeration type, its declaratio...
Git - Difference Between 'assume-unchanged' and 'skip-worktree'
...hows up when i do 'git status' as something to be staged. I would like to hide this particular change and not commit it. I won't make any other changes to the file.
...
git merge: apply changes to code that moved to a different file
... but my colleague moved that code to a new file in his branch. So when I did git merge my_branch his_branch , git did not notice that the code in the new file was the same as the old, and so none of my changes are there.
...
Transaction isolation levels relation with locks on table
...implementation and the algorithm they use: MVCC or Two Phase Locking.
CUBRID (open source RDBMS) explains the idea of this two algorithms:
Two-phase locking (2PL)
The first one is when the T2 transaction tries to change the A record,
it knows that the T1 transaction has already cha...
What is the purpose of setting a key in data.table?
...two things:
reorders the rows of the data.table DT by the column(s) provided (a, b) by reference, always in increasing order.
marks those columns as key columns by setting an attribute called sorted to DT.
The reordering is both fast (due to data.table's internal radix sorting) and memory effic...
How do CDI and EJB compare? interact?
...llows you to inject implementation into your service or whatever. The main idea is that class, where you inject, should be managed by EJB container.
Seems that CDI does understand what EJB is, so in Java EE 6 compliant server, in your servlet you can write both
@EJB EJBService ejbService;
and
@Inje...
Why should we NOT use sys.setdefaultencoding(“utf-8”) in a py script?
... time, when Python scans the environment. It has to be called in a system-wide module, sitecustomize.py, After this module has been evaluated, the setdefaultencoding() function is removed from the sys module.
The only way to actually use it is with a reload hack that brings the attribute back.
A...
Why does X[Y] join of data.tables not allow a full outer join, or a left join?
...ifferent so change to be the same as `merge`
setcolorder(le, names(mallx))
identical(le, mallx)
# [1] TRUE
If you want a full outer join
# the unique values for the keys over both data sets
unique_keys <- unique(c(X[,t], Y[,t]))
Y[X[J(unique_keys)]]
## t b a
## 1: 1 NA 1
## 2: 2 NA 4
## ...