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Check if a file exists with wildcard in shell script [duplicate]
... completely silent.
EDIT: Since this answer has got a bit of attention (and very useful critic remarks as comments), here is an optimization that also relies on glob expansion, but avoids the use of ls:
for f in /path/to/your/files*; do
## Check if the glob gets expanded to existing files.
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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)...
Declaration/definition of variables locations in ObjectiveC?
Ever since starting to work on iOS apps and objective C I've been really puzzled by the different locations where one could be declaring and defining variables. On one hand we have the traditional C approach, on the other we have the new ObjectiveC directives that add OO on top of that. Could you fo...
What is the meaning of “POSIX”?
What is POSIX? I have read the Wikipedia article and I read it every time I encounter the term. The fact is that I never really understood what it is.
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Difference between JAX-WS, Axis2 and CXF
...gs besides just JAX-WS. It has a compliant JAX-RS implementation as well and supports exposing services as both REST and SOAP very well. Has a W3C compliant SOAP/JMS implementation if that type of things is required. Basically, lots of stuff not available from the in-jdk JAX-WS impl.
Also see:...
Why is this program erroneously rejected by three C++ compilers?
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In the standard, §2.1/1 specifies:
Physical source file characters are mapped, in an implementation-defined manner, to the basic source character set (introducing new-line characters for end-of-line indicators) if necessary.
Yo...
How does one make random number between range for arc4random_uniform()?
so my goal in this codebit is to randomly roll two dice and as we all know your regular die only has 6 sides so I imported Foundation for access to arc4random_uniform(UInt32). I attempted using the range of (1..7) to avoid randomly getting 0 however that returned an error which I didn't enjoy too mu...
Python: fastest way to create a list of n lists
...None, n)]
It does not have to create a new int object in every iteration and is about 15 % faster on my machine.
Edit: Using NumPy, you can avoid the Python loop using
d = numpy.empty((n, 0)).tolist()
but this is actually 2.5 times slower than the list comprehension.
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Iterate a list as pair (current, next) in Python
...ometimes need to iterate a list in Python looking at the "current" element and the "next" element. I have, till now, done so with code like:
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Can code that is valid in both C and C++ produce different behavior when compiled in each language?
C and C++ have many differences, and not all valid C code is valid C++ code.
(By "valid" I mean standard code with defined behavior, i.e. not implementation-specific/undefined/etc.)
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