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How to find a deleted file in the project commit history?
...mit message
ba8d20e Another prior commit message affecting that file
cfea812 The first message for a commit in which that file appeared.
Checkout the file
If you choose the first-listed commit (the last chronologically, here bd8374c), the file will not be found, since it was deleted in that comm...
How do I replace NA values with zeros in an R dataframe?
...01.772 1106.315 1363.044 600
DT.for.set.sqln 787.3535 918.8733 1017.812 1002.042 1122.474 1321.860 600
Boxplot of Results
ggplot(perf_results, aes(x=expr, y=time/10^9)) +
geom_boxplot() +
xlab('Expression') +
ylab('Elapsed Time (Seconds)') +
scale_y_continuous(breaks = s...
Assign output of a program to a variable using a MS batch file
...
One way is:
application arg0 arg1 > temp.txt
set /p VAR=<temp.txt
Another is:
for /f %%i in ('application arg0 arg1') do set VAR=%%i
Note that the first % in %%i is used to escape the % after it and is needed when using the above code in a batch file rather than...
What exactly does big Ө notation represent?
...rst let's understand what big O, big Theta and big Omega are. They are all sets of functions.
Big O is giving upper asymptotic bound, while big Omega is giving a lower bound. Big Theta gives both.
Everything that is Ө(f(n)) is also O(f(n)), but not the other way around.
T(n) is said to be in Ө(f(n...
What are the differences between a multidimensional array and an array of arrays in C#?
... 4.776 4.635 5.864
7.414 13.196 11.940 11.832 11.675 11.811 11.812 12.964 11.885 11.751
11.355 10.788 10.527 10.541 10.745 10.723 10.651 10.930 10.639 10.595
Source code:
using System;
using System.Diagnostics;
static class ArrayPref
{
const string Format = "{0,7:0.000}...
Difference between Big-O and Little-O Notation
...0 <= f(x) <= k g(x) holds for all x > a.
Note that O(g) is the set of all functions for which this condition holds.
f ∈ o(g) says, essentially
For every choice of a constant k > 0, you can find a constant a such that the inequality 0 <= f(x) < k g(x) holds for all x > ...
Designing function f(f(n)) == -n
...(y) = -x, and f(-y) = x.
So, we need to divide all integers except 0 into sets of 4, but we have an odd number of such integers; not only that, if we remove the integer that doesn't have a positive counterpart, we still have 2(mod4) numbers.
If we remove the 2 maximal numbers left (by abs value), ...
Test for non-zero length string in Bash: [ -n “$var” ] or [ “$var” ]
...-----------------------------------+------------------------------------
unset| false false true false true true | false false false false true true
null | false false true false true true | false false false false true true
space| false true true true true false| true true true true f...
Algorithm to return all combinations of k elements from n
...rse memory and pretty quickly, you'll have problems by 20 elements in your set -- 20C3 = 1140. And if you want to iterate over the set it's best to use a modified gray code algorithm so you aren't holding all of them in memory. These generate the next combination from the previous and avoid repetiti...
Memoization in Haskell?
...d that f !! 143 exists, but its exact value is not calculated. It's still set as some unknown result of a calculation. The only exact values calculated are the ones needed.
So initially, as far as how much has been calculated, the program knows nothing.
f = ....
When we make the request f !! ...