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Get all non-unique values (i.e.: duplicate/more than one occurrence) in an array
... i, arr) => arr.indexOf(v) !== i && acc.indexOf(v) === -1 ? acc.concat(v) : acc, [])
– ZephDavies
Nov 29 '18 at 14:56
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C/C++ NaN constant (literal)?
...> offers the below functions:
#include <math.h>
double nan(const char *tagp);
float nanf(const char *tagp);
long double nanl(const char *tagp);
which are like their strtod("NAN(n-char-sequence)",0) counterparts and NAN for assignments.
// Sample C code
uint64_t u64;
double x;
x = nan("0...
Remove all special characters with RegExp
...cape it with a backslash like the latter group. if you don't it will also select 0-9 which is probably undesired.
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List of all special characters that need to be escaped in a regex
...a regex for matching the message. The template/message may contain special characters.
10 Answers
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unsigned int vs. size_t
...y removed all absolute guarantees about integer ranges (excluding unsigned char). The standard does not seem to contain the string '65535' or '65536' anywhere, and '+32767' only occurs (1.9:9) in a note as possible largest integer representable in int; no guarantee is given even that INT_MAX cannot ...
Combine two columns of text in pandas dataframe
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if both columns are strings, you can concatenate them directly:
df["period"] = df["Year"] + df["quarter"]
If one (or both) of the columns are not string typed, you should convert it (them) first,
df["period"] = df["Year"].astype(str) + df["quarter"]
Beware...
Maximum length of the textual representation of an IPv6 address?
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45 characters.
You might expect an address to be
0000:0000:0000:0000:0000:0000:0000:0000
8 * 4 + 7 = 39
8 groups of 4 digits with 7 : between them.
But if you have an IPv4-mapped IPv6 address, the last two groups can b...
Convert Elixir string to integer or float
...k String.to_integer/1 and String.to_float/1.
Hint: See also to_atom/1,to_char_list/1,to_existing_atom/1for other conversions.
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Best database field type for a URL
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The URL really might break the 65,535 byte row limit
Your queries won't select or update a bunch of URLs at once (or very often). This is because TEXT columns just hold a pointer inline, and the random accesses involved in retrieving the referenced data can be painful.
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Is there a way to escape a CDATA end token in xml?
...e 20 of the XML specification is quite clear:
[20] CData ::= (Char* - (Char* ']]>' Char*))
EDIT: This product rule literally means "A CData section may contain anything you want BUT the sequence ']]>'. No exception.".
EDIT2: The same section also reads:
Within a CDATA section, o...