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How do I check if a C++ std::string starts with a certain string, and convert a substring to an int?
...only match at that position or earlier. For example:
std::string test = "0123123";
size_t match1 = test.rfind("123"); // returns 4 (rightmost match)
size_t match2 = test.rfind("123", 2); // returns 1 (skipped over later match)
size_t match3 = test.rfind("123", 0); // returns std::string::npos (i...
svn : how to create a branch from certain revision of trunk
... actually specify this on the command line using your example:
svn copy -r123 http://svn.example.com/repos/calc/trunk \
http://svn.example.com/repos/calc/branches/my-calc-branch
Where 123 would be the revision number in trunk you want to copy. As others have noted, you can also use the @ synt...
Reshaping data.frame from wide to long format
... 1952 10,058
7: AFG Afghanistan 1953 23,557
8: ALB Albania 1953 11,123
9: AFG Afghanistan 1954 24,555
10: ALB Albania 1954 12,246
Some alternative notations:
melt(setDT(wide), id.vars = 1:2, variable.name = "year")
melt(setDT(wide), measure.vars = 3:7, variable.name = "year")
melt...
Why do x86-64 systems have only a 48 bit virtual address space?
...
lwn.net/SubscriberLink/655437/9a48cd3e7a8cbe8a <-- three years after this reply, we are already hitting these limits :) The HP Machine will have 320TB of memory and they can't provide it as a flat address space because of the 48-bit addressing limitation.
...
How to add images in select list?
...t.js; Icon/image select (combobox, dropdown)
Demo and download; http://bug7a.github.io/iconselect.js/
HTML usage;
<div id="my-icon-select"></div>
Javascript usage;
var iconSelect;
window.onload = function(){
iconSelect = new IconSelect("my-icon-select");
...
How to format strings in Java
...sing it. For example the following code MessageFormat.format("Number {0}", 1234)); depending on default locale can produce Number 1,234 instead of Number 1234.
– pavel_kazlou
Dec 4 '12 at 10:25
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grep using a character vector with multiple patterns
... oh I get it now. So its a compress way to output something like A1 | A2 so if one wanted all conditions then the collapse would be with an & sign, cool thanks.
– Ahdee
Feb 23 '18 at 15:41
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String comparison using '==' vs. 'strcmp()'
...r use == for string comparison. === is OK.
$something = 0;
echo ('password123' == $something) ? 'true' : 'false';
Just run the above code and you'll see why.
$something = 0;
echo ('password123' === $something) ? 'true' : 'false';
Now, that's a little better.
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Using Regular Expressions to Extract a Value in Java
...e matcher for pattern p and given string
Matcher m = p.matcher("Testing123Testing");
// if an occurrence if a pattern was found in a given string...
if (m.find()) {
// ...then you can use group() methods.
System.out.println(m.group(0)); // whole matched expression
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LINGO使用指南 - 更多技术 - 清泛网 - 专注C/C++及内核技术
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