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How to randomize (or permute) a dataframe rowwise and columnwise?
... Well, this is changing order of rows and columns, but what OP wanted is different: shuffle each column/row independently
– JelenaČuklina
Feb 2 '16 at 10:51
...
Timing a command's execution in PowerShell
... [switch]$quiet = $false
)
$start = Get-Date
try {
if ( -not $quiet ) {
iex $command | Write-Host
} else {
iex $command > $null
}
} finally {
$(Get-Date) - $start
}
}
Source: https://gist.github.com/bender-the-great...
PG::ConnectionBad - could not connect to server: Connection refused
...stmaster (PID 347) running in data directory "/usr/local/var/postgres"?
If so, rm postmaster.pid
Restart your server. On a mac using launchctl (with homebrew) the following commands will restart the server.
launchctl unload homebrew.mxcl.postgresql.plist
launchctl load -w homebrew.mxcl.postgre...
Get DateTime.Now with milliseconds precision
...lly speaking, you can't. Usually the system clock (which is where DateTime.Now gets its data from) has a resolution of around 10-15 ms. See Eric Lippert's blog post about precision and accuracy for more details.
If you need more accurate timing than this, you may want to look into using an NTP clie...
Relative frequencies / proportions with dplyr
Suppose I want to calculate the proportion of different values within each group. For example, using the mtcars data, how do I calculate the relative frequency of number of gears by am (automatic/manual) in one go with dplyr ?
...
Cannot create an array of LinkedLists in Java…?
...1000).get(2000)) will make LinkedList iterate 3000 times! Avoid LinkedList if anyone may be indexing into it. ArrayList will index faster, but Fredrik's solution is better overall.
– Steve Zobell
Mar 9 '17 at 20:08
...
Uploading Files in ASP.net without using the FileUpload server control
...edFile file = Request.Files["myFile"];
//check file was submitted
if (file != null && file.ContentLength > 0)
{
string fname = Path.GetFileName(file.FileName);
file.SaveAs(Server.MapPath(Path.Combine("~/App_Data/", fname)));
}
}
...
Apply style ONLY on IE
...bly to use an Internet Explorer conditional comment in your HTML:
<!--[if IE]>
<style>
.actual-form table {
width: 100%;
}
</style>
<![endif]-->
There are numerous hacks (e.g. the underscore hack) you can use that will allow you to target only IE within yo...
how to show lines in common (reverse diff)?
...hich I'd like to know the lines in common rather than the lines which are different between them. Command line unix or windows is fine.
...
How can I detect when an Android application is running in the emulator?
I would like to have my code run slightly differently when running on the emulator than when running on a device. ( For example , using 10.0.2.2 instead of a public URL to run against a development server automatically.) What is the best way to detect when an Android application is running in the em...