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Pass a data.frame column name to a function
...l_name,col1,col2){
df$col_name <- df$col1 + df$col2
df
}
#Call foo() like this:
foo(dat,z,x,y)
The problem here is that df$col1 doesn't evaluate the expression col1. It simply looks for a column in df literally called col1. This behavior is described in ?Extract under the secti...
Compress files while reading data from STDIN
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Yes, gzip will let you do this. If you simply run gzip > foo.gz, it will compress STDIN to the file foo.gz. You can also pipe data into it, like some_command | gzip > foo.gz.
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Why do I need to explicitly push a new branch?
... did git push my branch was not uploaded to the repository. I had to actually do: git push -u origin --all .
Why is this? Isn't a branch a new change to be pushed by default? Why do I need to run the second command?
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What is the HTML tabindex attribute?
... to set the order but just make your element focusable use tabindex="0" on all such elements:
<div tabindex="0"></div>
Also, if you don't want it to be focusable via the tab key then use tabindex="-1". For example, the below link will not be focused while using tab keys to traverse.
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Why does Java's hashCode() in String use 31 as a multiplier?
... i == (i << 5) - i. Modern VMs do this sort of optimization automatically.
(from Chapter 3, Item 9: Always override hashcode when you override equals, page 48)
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How do I make UILabel display outlined text?
All I want is a one pixel black border around my white UILabel text.
15 Answers
15
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Boolean vs boolean in Java
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It should be noted the a Boolean actually has 3 states... true, false and null where a boolean has the logical 2 states (true and false)
– respectTheCode
Jun 6 '14 at 15:46
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Converting string to byte array in C#
... Apr 18 '13 at 0:54
Timothy RandallTimothy Randall
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Exposing a port on a live Docker container
...e -p flag with docker run to assign ports, but once a container is actually running, is there a command to open/map additional ports live?
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Change text from “Submit” on input tag
...(including <img> here).
<button type="submit" class="like" name="foo" value="bar">Like</button>
Note that support for <button> is dodgy in older versions of Internet Explorer.
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