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Memoization in Haskell?
...alling, for example: fix f 123 = 144
We could memoize this by defining:
f_list :: [Int]
f_list = map (f faster_f) [0..]
faster_f :: Int -> Int
faster_f n = f_list !! n
That performs passably well, and replaces what was going to take O(n^3) time with something that memoizes the intermediate r...
Convert Python dictionary to JSON array
...
If you are fine with non-printable symbols in your json, then add ensure_ascii=False to dumps call.
>>> json.dumps(your_data, ensure_ascii=False)
If ensure_ascii is false, then the return value will be a
unicode instance subject to normal Python str to unicode
coercion rules in...
sizeof single struct member in C
...ic way to do it, another would be to use a macro like this:
#define member_size(type, member) sizeof(((type *)0)->member)
and use it like this:
typedef struct
{
float calc;
char text[255];
int used;
} Parent;
typedef struct
{
char flag;
char text[member_size(Parent, text)...
How to convert Strings to and from UTF8 byte arrays in Java
...]:
String s = "some text here";
byte[] b = s.getBytes(StandardCharsets.UTF_8);
Convert from byte[] to String:
byte[] b = {(byte) 99, (byte)97, (byte)116};
String s = new String(b, StandardCharsets.US_ASCII);
You should, of course, use the correct encoding name. My examples used US-ASCII and UT...
What is the difference between “long”, “long long”, “long int”, and “long long int” in C++?
...stdint.h> seems to be the proper way to ensure bitwidths using the int##_t types, though it's not yet part of the standard.]
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Validating IPv4 addresses with regexp
...|2[0-4][0-9]|[01]?[0-9][0-9]?)(\.|$)){4}$ get same result debuggex.com/r/mz_-0dEm3wseIKqK, pretty similar with @Mark Byers answer
– Sllouyssgort
Mar 24 '16 at 11:55
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How to get position of a certain element in strings vector, to use it as an index in ints vector?
...nting to the element, simply subtract v.begin() from the iterator:
ptrdiff_t pos = find(Names.begin(), Names.end(), old_name_) - Names.begin();
Now you need to check pos against Names.size() to see if it is out of bounds or not:
if(pos >= Names.size()) {
//old_name_ not found
}
vector i...
Getting LaTeX into R Plots
...t interferes with the ggplot ~ # tikzDecice combo
colnames(AR) <- c("$V_{BB}[V]$", "$V_{RB}[V]$" , "$V_{RC}[V]$" , "$I_B[\\mu A]$" , "IC" , "$V_{BE}[V]$" , "$V_{CE}[V]$" , "beta" , "$I_E[mA]$")
# make sure the working directory is where you want your tikz file to go
setwd("~/TexImageFolder/")
...
How can I generate a unique ID in Python? [duplicate]
...have to manually kill uuidd as root. I worked around this by setting uuid._uuid_generate_time and uuid._uuid_generate_random to None so the uuid module never used the native implementation. (That should really be an option anyway; generating V4 random UUIDs causing a daemon to be started is comple...
Get the value of an instance variable given its name
...
The most idiomatic way to achieve this is:
some_object.instance_variable_get("@#{name}")
There is no need to use + or intern; Ruby will handle this just fine. However, if you find yourself reaching into another object and pulling out its ivar, there's a reasonably good ...