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To find whether a column exists in data frame or not
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all(c("d", "e", "f") %in% colnames(dat))
– skan
Jul 28 '17 at 19:59
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How to implement Android Pull-to-Refresh
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Finally, Google released an official version of the pull-to-refresh library!
It is called SwipeRefreshLayout, inside the support library, and the documentation is here:
Add SwipeRefreshLayout as a parent of view which will b...
More than 10 lines in a node.js stack error?
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If you'd like to see stack trace that spans over setTimeout/setInterval calls, then more sophisticated https://github.com/mattinsler/longjohn would be the way to go.
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How to update a value, given a key in a hashmap?
...e computeIfPresent method and supply it a mapping function, which will be called to compute a new value based on existing one.
For example,
Map<String, Integer> words = new HashMap<>();
words.put("hello", 3);
words.put("world", 4);
words.computeIfPresent("hello", (k, v) -> v + 1);
S...
Converting String to “Character” array in Java
...Points())
map each 'character' value to Character (you need to cast to actually say that its really a char, and then Java will box it automatically to Character)
get the resulting array by calling toArray()
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Text overflow ellipsis on two lines
...lt;div class="ellipsis">
<div>
<p>
Call me Ishmael. Some years ago – never mind how long precisely – having
little or no money in my purse, and nothing particular to interest me on
shore, I thought I would sail about a little and see...
Detect enter press in JTextField
...Event e){
//statements!!!
}});
all you need to do is addActionListener to the JTextField like above! After you press Enter the action will performed what you want at the statement!
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Why I cannot cout a string?
...-defined <xstring> header (never include that directly)). While that allows you to use the string class, the relevant operator<< is defined in the <string> header itself, so you must include that manually. Also relying on other headers to indirectly include the definition of std::b...
Limiting number of displayed results when using ngRepeat
...lays phones. I’m on step 5 and I thought as an experiment I’d try to allow users to specify how many they’d like to be shown. The view looks like this:
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iOS: Access app-info.plist variables in code
...ode (right click the info.plist - select Open As) then you will get to see all the various key names you can use.
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