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How to append rows to an R data frame
...ined as:
# pre-allocate space
f3 <- function(n){
df <- data.frame(m>x m> = numeric(n), y = character(n), stringsAsFactors = FALSE)
for(i in 1:n){
df$m>x m>[i] <- i
df$y[i] <- toString(i)
}
df
}
Here's a similar approach, but one where the data.frame is created as the last step.
...
WPF ListView turn off selection
...gt;
<ListView.ItemContainerStyle>
<Style TargetType="{m>x m>:Type ListViewItem}">
<Style.Triggers>
<Trigger Property="IsSelected"
Value="True">
<Setter Property="Background"
...
Behaviour of increment and decrement operators in Python
...d - unary operators only work on numbers, but I presume that you wouldn't em>x m>pect a hypothetical ++ operator to work on strings.)
++count
Parses as
+(+count)
Which translates to
count
You have to use the slightly longer += operator to do what you want to do:
count += 1
I suspect the ++ an...
How to find the size of localStorage
...
Em>x m>ecute this snippet in JavaScript console (one line version):
var _lsTotal=0,_m>x m>Len,_m>x m>;for(_m>x m> in localStorage){ if(!localStorage.hasOwnProperty(_m>x m>)){continue;} _m>x m>Len= ((localStorage[_m>x m>].length + _m>x m>.length)* 2);_lsTotal+=_m>x m>Len;...
Breaking out of nested loops [duplicate]
Is there an easier way to break out of nested loops than throwing an em>x m>ception? (In Perl, you can give labels to each loop and at least continue an outer loop.)
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What's a concise way to check that environment variables are set in a Unim>x m> shell script?
I've got a few Unim>x m> shell scripts where I need to check that certain environment variables are set before I start doing stuff, so I do this sort of thing:
...
What is an idempotent operation?
...effect if it is called more than once with the same input parameters. For em>x m>ample, removing an item from a set can be considered an idempotent operation on the set.
In mathematics, an idempotent operation is one where f(f(m>x m>)) = f(m>x m>). For em>x m>ample, the abs() function is idempotent because abs(abs(m>x m>))...
Header files for m>x m>86 SIMD intrinsics
Which header files provide the intrinsics for the different m>x m>86 SIMD instruction set em>x m>tensions (MMm>X m>, SSE, AVm>X m>, ...)? It seems impossible to find such a list online. Correct me if I'm wrong.
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How to compare type of an object in Python?
...use basestr, not str. otherwise you will not pick unicode. (although for 3.m>x m> I think str is the basestr)
– hasen
Apr 3 '09 at 0:45
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What algorithm does Readability use for em>x m>tracting tem>x m>t from URLs?
For a while, I've been trying to find a way of intelligently em>x m>tracting the "relevant" tem>x m>t from a URL by eliminating the tem>x m>t related to ads and all the other clutter.After several months of researching, I gave it up as a problem that cannot be accurately determined. (I've tried different ways but ...