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How do I create a unique ID in Java? [duplicate]
...ignificantBits());
}
private static String toIDString(long i) {
char[] buf = new char[32];
int z = 64; // 1 << 6;
int cp = 32;
long b = z - 1;
do {
buf[--cp] = DIGITS66[(int)(i & b)];
i >>>= 6;
} while (i != 0);
re...
Convert data.frame column format from character to factor
... the format (class) of some columns of my data.frame object ( mydf ) from charactor to factor .
6 Answers
...
Why is it slower to iterate over a small string than a small list?
...string took longer than doing the same operation on a list of small single character strings. Any explanation? It's almost 1.35 times as much time.
...
Boost.Asio的简单使用(Timer,Thread,Io_service类) - C/C++ - 清泛网 - 专注C/C++及内核技术
...I标准发送数据。)
using boost::asio::ip::tcp;
int main(int argc, char* argv[])
{
try
{
if (argc != 2)
{
std::cerr << "Usage: client <host>" << std::endl;
return 1;
}
用asio进行网络连接至少需要一个boost::asi...
Replace all non Alpha Numeric characters, New Lines, and multiple White Space with one Space
.../[\W_]+/g," ");
\W is the negation of shorthand \w for [A-Za-z0-9_] word characters (including the underscore)
Example at regex101.com
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How can I get a file's size in C++? [duplicate]
...
#include <fstream>
std::ifstream::pos_type filesize(const char* filename)
{
std::ifstream in(filename, std::ifstream::ate | std::ifstream::binary);
return in.tellg();
}
See http://www.cplusplus.com/doc/tutorial/files/ for more information on files in C++.
edit: this answ...
Why can I add named properties to an array as if it were an object?
...cts, just slightly modified (with a few more functions).
Functions like:
concat
every
filer
forEach
join
indexOf
lastIndexOf
map
pop
push
reverse
shift
slice
some
sort
splice
toSource
toString
unshift
valueOf
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What is the default initialization of an array in Java?
...t is a 0.
For float/double that is a 0.0
For booleans that is a false.
For char that is the null character '\u0000' (whose decimal equivalent is 0).
When you create an array of something, all entries are also zeroed. So your array contains five zeros right after it is created by new.
Note (based...
How do I remove the first characters of a specific column in a table?
In SQL, how can I remove the first 4 characters of values of a specific column in a table? Column name is Student Code and an example value is ABCD123Stu1231 .
I want to remove first 4 chars from my table for all records
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COUNT DISTINCT with CONDITIONS
...bination of Tag & Entry ID when [Entry Id]>0
select count(distinct(concat(tag,entryId)))
from customers
where id>0
In the output it will display the count of unique values
Hope this helps
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