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Mechanisms for tracking DB schema changes [closed]
...ed code to a production server) but we're still doing database updates manually. I would like to find or create a solution that allows us to work efficiently across servers with different environments while continuing to use Subversion as a backend through which code and DB updates are pushed aroun...
Remove rows with duplicate indices (Pandas DataFrame and TimeSeries)
...Pandas Index itself:
df3 = df3[~df3.index.duplicated(keep='first')]
While all the other methods work, the currently accepted answer is by far the least performant for the provided example. Furthermore, while the groupby method is only slightly less performant, I find the duplicated method to be mor...
Parse query string into an array
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Technically PHP would also treat ?key=lorem&key=ipsum as if you only provided key=ipsum if that were the query string on the URL. And I think it's considered invalid to reuse the key and expect consistent results or that all ins...
Is there a builtin identity function in python?
...hink about the signature and time costs.
So a better way to do it is actually (a lambda avoids naming the function):
_ = lambda *args: args
advantage: takes any number of parameters
disadvantage: the result is a boxed version of the parameters
OR
_ = lambda x: x
advantage: doesn't change...
Read error response body in Java
...ere is to code like this:
HttpURLConnection httpConn = (HttpURLConnection)_urlConnection;
InputStream _is;
if (httpConn.getResponseCode() < HttpURLConnection.HTTP_BAD_REQUEST) {
_is = httpConn.getInputStream();
} else {
/* error from server */
_is = httpConn.getErrorStream();
}
...
CSV new-line character seen in unquoted field error
...csv file itself, but this might work for you, give it a try, replace:
file_read = csv.reader(self.file)
with:
file_read = csv.reader(self.file, dialect=csv.excel_tab)
Or, open a file with universal newline mode and pass it to csv.reader, like:
reader = csv.reader(open(self.file, 'rU'), dialec...
How do I create a URL shortener?
...two character checksum to the url. That would prevent direct iteration of all the urls in your system. Something simple like f(checksum(id) % (62^2)) + f(id) = url_id
– koblas
Sep 4 '10 at 13:53
...
Calling shell functions with xargs
...
Exporting the function should do it (untested):
export -f echo_var
seq -f "n%04g" 1 100 | xargs -n 1 -P 10 -I {} bash -c 'echo_var "$@"' _ {}
You can use the builtin printf instead of the external seq:
printf "n%04g\n" {1..100} | xargs -n 1 -P 10 -I {} bash -c 'echo_var "$@"' _ {}
...
Can I protect against SQL injection by escaping single-quote and surrounding user input with single-
...
First of all, it's just bad practice. Input validation is always necessary, but it's also always iffy.
Worse yet, blacklist validation is always problematic, it's much better to explicitly and strictly define what values/formats you a...
Default visibility of class methods in PHP
...sibility.
<?php
class Example {
public $name;
public function __construct() {
$this -> age = 9; // age is now public
$this -> privateFunction();
}
private function privateFunction() {
$this -> country = "USA"; // this is also public
}
}
...