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How to reverse a string in Go?
...size of the input in bytes. It does not correspond to its length. - Not all utf8's runes are of the same size. It can be either 1, 2, 4, or 8. - You should use unicode/ut8 package's method RuneCountInString to get the length of the rune.
– Anvesh Checka
M...
How to access the last value in a vector?
...s not from an aesthetical but performance-oriented point of view, I've put all of the above suggestions through a benchmark. To be precise, I've considered the suggestions
x[length(x)]
mylast(x), where mylast is a C++ function implemented through Rcpp,
tail(x, n=1)
dplyr::last(x)
x[end(x)[1]]]
rev...
Using std Namespace
...efined vector.
I am always against using using namespace std;. It imports all sorts of names into the global namespace and can cause all sorts of non-obvious ambiguities.
Here are some common identifiers that are in the std namespace: count, sort, find, equal, reverse. Having a local variable call...
Create code first, many to many, with additional fields in association table
...join table. In a many-to-many relationship EF manages the join table internally and hidden. It's a table without an Entity class in your model. To work with such a join table with additional properties you will have to create actually two one-to-many relationships. It could look like this:
public c...
Is there a way to make GHC provide the type class constraints of typed holes?
...ng out-of-scope types
(use -fprint-potential-instances to see them all)
• In the expression: show _
In an equation for ‘it’: it = show _
<interactive>:3:6: error:
• Found hole: _ :: a0
Where: ‘a0’ is an ambiguous type variable
• In the first argum...
case-insensitive list sorting, without lowercasing the result?
...
In Python 3.3+ there is the str.casefold method that's specifically designed for caseless matching:
sorted_list = sorted(unsorted_list, key=str.casefold)
In Python 2 use lower():
sorted_list = sorted(unsorted_list, key=lambda s: s.lower())
It works for both normal and unicode strin...
Linux - Replacing spaces in the file names
...umber of files in a folder, and I want to replace every space character in all file names with underscores. How can I achieve this?
...
Django database query: How to get object by id?
Django automatically creates an id field as primary key.
6 Answers
6
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Proper Linq where clauses
...collection where as in the first one, it's applying the first predicate to all items first and the result (which is narrowed down at this point) is used for the second predicate and so on. The results get narrowed down every pass but still it involves multiple passes.
Also the chaining (first metho...
What's the fastest way to merge/join data.frames in R?
...(y) from main.d group by g1, g2"))
)
The outputs from the two benchmark call comparing the merge calculations are:
Joining by: x
test replications elapsed relative user.self sys.self user.child sys.child
3 data.table 1 0.34 1.000000 0.31 0.01 NA NA
2 ...