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Where should Rails 3 custom validators be stored?
...go in a /lib or /lib/validators directory of a project. I've found (by reading an answer to another post) that they only seem to work in config/initializers . Does anyone know, or have a pointer to official documentation that shows where custom validators should live?
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from list of integers, get number closest to a given value
...s, like {1: "a", 2: "b"}. This method takes O(n) time.
If the list is already sorted, or you could pay the price of sorting the array once only, use the bisection method illustrated in @Lauritz's answer which only takes O(log n) time (note however checking if a list is already sorted is O(n) and ...
Python: Continuing to next iteration in outer loop
...to me that the behavior of for-else is more complicated, more difficult to read, and probably more abused (if not an outright mistake) than named loops would be. I think I would have used a different keyword than else - perhaps something like resume would have been good? You break in the loop and th...
Change type of varchar field to integer: “cannot be cast automatically to type integer”
...olumn_name::integer'
If you are interested to find more about this topic read this article: https://kolosek.com/rails-change-database-column
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pandas three-way joining multiple dataframes on columns
...ething like this:
filenames = ['fn1', 'fn2', 'fn3', 'fn4',....]
dfs = [pd.read_csv(filename, index_col=index_col) for filename in filenames)]
dfs[0].join(dfs[1:])
With @zero's data, you could do this:
df1 = pd.DataFrame(np.array([
['a', 5, 9],
['b', 4, 61],
['c', 24, 9]]),
column...
Cannot import the keyfile 'blah.pfx' - error 'The keyfile may be password protected'
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I had the same issue and deleting the store and reading didn't work. I had to do the following.
Get a copy of OpenSSL. It is available for Windows. Or use a Linux box as they all pretty much all have it.
Run the following to export to a key file:
openssl pkcs12 -in cert...
How do I convert an integer to string as part of a PostgreSQL query?
...Then an example of when this could be relevant. In my case, I found this thread because I actually had to convert an integer to a string - not for comparison but for using inside an aggregate function that would fail, if the argument was not a string. In which case, this was not an answer to the que...
Are Java static initializers thread safe?
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Yes, Java static initializers are thread safe (use your first option).
However, if you want to ensure that the code is executed exactly once you need to make sure that the class is only loaded by a single class-loader. Static initialization is performed once p...
How to make an AJAX call without jQuery?
...tion loadXMLDoc() {
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == XMLHttpRequest.DONE) { // XMLHttpRequest.DONE == 4
if (xmlhttp.status == 200) {
document.getElementById("myDiv").innerHTML = xmlhtt...
Why is the use of alloca() not considered good practice?
...deed, but it shows also how easy it is missed, as I hadn't seen it despite reading all responses before posting.
– Patrick Schlüter
Aug 2 '10 at 9:50
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