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What is the printf format specifier for bool?
...
@HelloGoodbye, passing a single char * to printf() is considered bad practice because it's really supposed to be a format string, and an unescaped percent sign might cause your program to blow up (see here for more). Thus, printf("%s", ...) is safer. If you...
Find the max of two or more columns with pandas
...DataFrame(np.random.randn(5, 1000))
perfplot.show(
setup=lambda n: pd.concat([df_] * n, ignore_index=True),
kernels=[
lambda df: df.assign(new=df.max(axis=1)),
lambda df: df.assign(new=df.values.max(1)),
lambda df: df.assign(new=np.nanmax(df.values, axis=1)),
...
How to split a comma-separated value to columns
...
CREATE FUNCTION [dbo].[fn_split_string_to_column] (
@string NVARCHAR(MAX),
@delimiter CHAR(1)
)
RETURNS @out_put TABLE (
[column_id] INT IDENTITY(1, 1) NOT NULL,
[value] NVARCHAR(MAX)
)
AS
BEGIN
DECLARE @value NVARCHAR(MAX),
@pos INT = 0,
@len INT =...
MySQL - ORDER BY values within IN()
...
just use
order by INSTR( ',B,C,D,A,' , concat(',' , `field`, ',' ) )
avoid the situation like
INSTR('1,2,3,11' ,`field`)
will end with unordered result row : 1 and 11 alternant
s...
What does “dereferencing” a pointer mean?
...pointer scenario
Consider in C, given a pointer such as p below...
const char* p = "abc";
...four bytes with the numerical values used to encode the letters 'a', 'b', 'c', and a 0 byte to denote the end of the textual data, are stored somewhere in memory and the numerical address of that data is...
What's the best way to build a string of delimited items in Java?
...lar to the one you refer to in Ruby:
StringUtils.join(java.lang.Iterable,char)
Java 8:
Java 8 provides joining out of the box via StringJoiner and String.join(). The snippets below show how you can use them:
StringJoiner
StringJoiner joiner = new StringJoiner(",");
joiner.add("01").add("02")...
Getting the closest string match
...splits Text into an array of substrings, each substring
' delimited by any character in DelimChars. Only a single character
' may be a delimiter between two substrings, but DelimChars may
' contain any number of delimiter characters. It returns a single element
' array containing all of text if Deli...
Removing colors from output
...hould probably be (m|K) or [mK], because you're not trying to match a pipe character. But that's not important right now.)
If you switch that final match in your command to [mGK] or (m|G|K), you should be able to catch that extra control sequence.
./somescript | sed -r "s/\x1B\[([0-9]{1,3}(;[0-9]{...
What does the restrict keyword mean in C++?
... saved, as mentioned by supercat and michael.
Consider for example:
void f(char *restrict p1, char *restrict p2, size_t size) {
for (size_t i = 0; i < size; i++) {
p1[i] = 4;
p2[i] = 9;
}
}
Because of restrict, a smart compiler (or human), could optimize that to:
mem...
Java `final` method: what does it promise?
...lass.
Reliability and Contract -- Objects are composed of primitives (int, char, double, etc.) and/or other Objects. Not all operations applicable to those components should be applicable or even logical when they are used in the bigger Object. Methods with the final modifier can be used to ensure t...