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How to add leading zeros?
...formatC is an interface to the C function printf. Using it requires some knowledge of the arcana of that underlying function (see link). In this case, the important points are the width argument, format being "d" for "integer", and a "0" flag for prepending zeroes.
formatC(anim, width = 6, format...
Spring MVC: How to perform validation?
I would like to know what is the cleanest and best way to perform form validation of user inputs. I have seen some developers implement org.springframework.validation.Validator . A question about that: I saw it validates a class. Does the class have to be filled manually with the values from the us...
How do you beta test an iphone app?
...s to unlimited users, but it does cost some $$ unlike TestFlight which has now been integrated directly into iTunes Connect.
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How do I convert an HttpRequestBase into an HttpRequest object?
...Link is dead; developmentalmadness.com domain expired, GoDaddy filler page now
– Chris Moschini
Aug 6 '12 at 18:47
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Nodejs Event Loop
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How did you know these things, can you point me to the source?
– Suraj Jain
Mar 31 at 19:24
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Why can't decimal numbers be represented exactly in binary?
... factors other than 2 or 5 will not have a terminating representation.
So now going back to bases 10 and 2, we see that any rational with a terminating 10-representation will be of the form p/q exactly when q has only 2s and 5s in its prime factorisation; and that same number will have a terminatin...
Parsing command-line arguments in C?
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To my knowledge, the three most popular ways how to parse command line arguments in C are:
Getopt (#include <unistd.h> from the POSIX C Library), which can solve simple argument parsing tasks. If you're a bit familiar with b...
Shrink a YouTube video to responsive width
...the same dimensions but for whatever reason the CSS in the accepted answer now letterboxes all our videos. Black bands across top and bottom.
I've tickered around with the sizes and settled on getting rid of the top padding and changing the bottom padding to 56.45%. Seems to look good.
.videowra...
Remove columns from dataframe where ALL values are NA
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dplyr now has a select_if verb that may be helpful here:
library(dplyr)
temp <- data.frame(x = 1:5, y = c(1,2,NA,4, 5), z = rep(NA, 5))
not_all_na <- function(x) any(!is.na(x))
not_any_na <- function(x) all(!is.na(x))
&g...
Is C++ context-free or context-sensitive?
...ble undertaking. Even writing a C++ program is difficult, and as far as I know none have been proven correct. This is why the standard does not attempt to provide a complete formal grammar, and why it chooses to write some of the parsing rules in technical English.
What looks like a formal grammar ...