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Dynamically select data frame columns using $ and a character value
...ldname)) {
print("Bad file column name")
}
# Here we use the hash table implementation where
# we have a string key and list value so we need actual strings,
# not Factors
file[cptcodefieldname] = as.character(file[cptcodefieldname])
file[icdcodefieldname] = as.character(file[icdcodefieldn...
How can I check if multiplying two numbers in Java will cause an overflow?
...t; 0 && b < maximum / a))
{
// Overflow
}
Here's a little table I whipped up to check this, pretending that overflow happens at -10 or +10:
a = 5 b = 2 2 > 10 / 5
a = 2 b = 5 5 > 10 / 2
a = -5 b = 2 2 > -10 / -5
a = -2 b = 5 5 > -10 / -...
Rails Migration: Remove constraint
I have a table in a Rails application which (in schema.rb) looks like:
2 Answers
2
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Why does ConcurrentHashMap prevent null keys and values?
...and get calls, causing this snippet to return a null that was never in the table, rather than the desired KeyNotPresentException.
Normally you would solve that by synchronizing, but with a concurrent map that of course won't work. Hence the signature for get had to change, and the only way to do th...
Why do we need a fieldset tag?
... form with many different areas of interest in a logical way without using tables. The fieldset tag can be used to create boxes around selected elements and the legend tag will give a caption to those elements. In this way form elements can be grouped together into identified categories.
Different ...
Prevent nginx 504 Gateway timeout using PHP set_time_limit()
... attempts to make a connection to a database and then creates many initial tables and fills it with data .. that could take quite some time before a response.
– imme
Nov 20 '17 at 18:11
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Maven2: Missing artifact but jars are in place
...
Wow, this had me tearing my hair out, banging my head against walls, tables and other things.
I had the same or a similar issue as the OP where it was either missing / not downloading the jar files or downloading them, but not including them in the Maven dependencies with the same error messag...
Get selected element's outer HTML
...nction; the issue is that I need the HTML including the selected object (a table row in this case, where .html() only returns the cells inside the row).
...
How do I truncate a .NET string?
...t its length is not longer than a given value. I am writing to a database table and want to ensure that the values I write meet the constraint of the column's datatype.
...
How to cast an Object to an int
...ue index for each object, like to auto incremented ID values in a database table (and unlike to identity hash which is not unique). A simple sample implementation for this:
class ObjectIndexer {
private int index = 0;
private Map<Object, Integer> map = new WeakHashMap<>();
...