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How to append rows to an R data frame
...rs of the type you want for each column, insert values into those vectors, and then, at the end, create your data.frame.
Continuing with Julian's f3 (a preallocated data.frame) as the fastest option so far, defined as:
# pre-allocate space
f3 <- function(n){
df <- data.frame(x = numeric(n)...
How do you crash a JVM?
...e JVM immediately without proper cleanup. But apart from that, native code and resource exhaustion are the most likely answers. Alternatively you can go looking on Sun's bug tracker for bugs in your version of the JVM, some of which allow for repeatable crash scenarios. We used to get semi-regular c...
python requests file upload
... uploading a file using Python requests library. I searched Stack Overflow and no one seemed to have the same problem, namely, that the file is not received by the server:
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Why does Java switch on contiguous ints appear to run faster with added cases?
... (bytecode instruction tableswitch).
However, once the JIT starts its job and compiles the bytecode into assembly, the tableswitch instruction does not always result in an array of pointers: sometimes the switch table is transformed into what looks like a lookupswitch (similar to an if/else if stru...
How to sort by two fields in Java?
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@Ralph: I have amended my answer, and added a brief description.
– Richard H
Jan 26 '11 at 14:53
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Java LinkedHashMap get first or last entry
...ions has its own LinkedMap implementation, which has methods like firstKey and lastKey, which do what you're looking for. The interface is considerably richer.
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How do I trim leading/trailing whitespace in a standard way?
Is there a clean, preferably standard method of trimming leading and trailing whitespace from a string in C? I'd roll my own, but I would think this is a common problem with an equally common solution.
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How to show git log history for a sub directory of a git repo?
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For people skim-reading, this shows changes in A and B, not just A as OP requested
– aidan
Jan 29 '18 at 5:55
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Sending email with PHP from an SMTP server
...l through a server that requires SMTP Auth, you really need to specify it, and set the host, username and password (and maybe the port if it is not the default one - 25).
For example, I usually use PHPMailer with similar settings to this ones:
$mail = new PHPMailer();
// Settings
$mail->IsSMTP...
What are the Ruby File.open modes and options?
Ruby's File.open takes modes and options as arguments. Where do I find a complete list of modes and options?
2 Answers
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