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Best way to test if a row exists in a MySQL table
I'm trying to find out if a row exists in a table. Using MySQL, is it better to do a query like this:
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Why is the shovel operator (
I am working through Ruby Koans.
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Understanding exactly when a data.table is a reference to (vs a copy of) another data.table
I'm having a little trouble understanding the pass-by-reference properties of data.table . Some operations seem to 'break' the reference, and I'd like to understand exactly what's happening.
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How to check if a string “StartsWith” another string?
How would I write the equivalent of C#'s String.StartsWith in JavaScript?
19 Answers
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Replacing NAs with latest non-NA value
In a data.frame (or data.table), I would like to "fill forward" NAs with the closest previous non-NA value. A simple example, using vectors (instead of a data.frame ) is the following:
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Prevent flicker on webkit-transition of webkit-transform [duplicate]
For some reason, right before my animation of the webkit-transform property occurs, there is a slight flicker. Here is what I am doing:
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Why is January month 0 in Java Calendar?
In java.util.Calendar , January is defined as month 0, not month 1. Is there any specific reason to that ?
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In javascript, is an empty string always false as a boolean?
in javascript,
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Difference between variable declaration syntaxes in Javascript (including global variables)?
Is there any difference between declaring a variable:
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