大约有 40,000 项符合查询结果（耗时：0.0446秒） [XML]
“Diff” an image using ImageMagick
...th layers, 3) remove alpha channels from both layers in the Layers tab, 4) select the G + B channels on one layer, select all and clear the channels with black color, the same with the R + B channels on the second layer, 4) set Screen mode for the upper layer in the Layers tab.
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How to check status of PostgreSQL server Mac OS X
...using psql to run a simple query and checking the exit code, e.g. psql -c 'SELECT 1', or use pg_isready to check the connection status.
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Can you use hash navigation without affecting history?
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Unless you use :target selectors ... then history functions are useless, as that part of the spec (css interaction with history ops) seems to be not defined currently, and style does not get recomputed on history replace by most/all browsers.
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Format number to 2 decimal places
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Show as decimal
Select ifnull(format(100.00, 1, 'en_US'), 0)
100.0
Show as Percentage
Select concat(ifnull(format(100.00, 0, 'en_US'), 0), '%')
100%
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Unable to install gem - Failed to build gem native extension - cannot load such file — mkmf (LoadErr
... reinstalled like this:
rm -rf /Library/Developer/CommandLineTools
xcode-select --install
Then i ran the previous command again:
open /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg
After install the error was fixed!
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Representing and solving a maze given an image
...otoshop in Image -> Adjustments -> Threshold.
Make sure threshold is selected right. Use the Magic Wand Tool with 0 tolerance, point sample, contiguous, no anti-aliasing. Check that edges at which selection breaks are not false edges introduced by wrong threshold. In fact, all interior points ...
Check if a div exists with jquery [duplicate]
...myDiv.length){
//you can now reuse $myDiv here, without having to select it again.
}
});
A selector always returns a jQuery object, so there shouldn't be a need to check against null (I'd be interested if there is an edge case where you need to check for null - but I don't think the...
Summarizing multiple columns with dplyr? [duplicate]
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I mean, the behavior like in select would be great: summarize(df, a:c, d=paste(d, collaspe =',' ) . Just want to put more original columns in for reference
– biocyberman
Aug 8 '15 at 17:28
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How can I change an element's text without changing its child elements?
...to_change.nodeValue = 'new text';
Of course, you can still use jQuery to select the <div> in the first place (i.e. var your_div = $('your_div').get(0);).
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Running PostgreSQL in memory only
...atement = ds.getConnection().createStatement();
statement.execute("SELECT 1");
ResultSet resultSet = statement.getResultSet();
resultSet.next();
int resultSetInt = resultSet.getInt(1);
assertEquals("A basic SELECT query succeeds", 1, resultSetInt);
}
}
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