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In Java, how do I convert a byte array to a string of hex digits while keeping leading zeros? [dupli

...oach would be to check how many digits are output by Integer.toHexString() and add a leading zero to each byte if needed. Something like this: public static String toHexString(byte[] bytes) { StringBuilder hexString = new StringBuilder(); for (int i = 0; i < bytes.length; i++) { ...
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What does (x ^ 0x1) != 0 mean?

...expression is false if x == 1. So the test is the same as: if (x != 1) and is therefore (arguably) unnecessarily obfuscated. share | improve this answer | follow ...
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What does appending “?v=1” to CSS and Javascript URLs in link and script tags do?

...ing at a HTML 5 boilerplate template (from http://html5boilerplate.com/ ) and noticed the use of "?v=1" in URLs when referring to CSS and Javascript files. ...
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What does ||= (or-equals) mean in Ruby?

... This question has been discussed so often on the Ruby mailing-lists and Ruby blogs that there are now even threads on the Ruby mailing-list whose only purpose is to collect links to all the other threads on the Ruby mailing-list that discuss this issue. Here's one: The definitive list of ||= ...
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Need a simple explanation of the inject method

...umulator: the result of each run of the block is stored in the accumulator and then passed to the next execution of the block. In the case of the code shown above, you are defaulting the accumulator, result, to 0. Each run of the block adds the given number to the current total and then stores the r...
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How to recursively find and list the latest modified files in a directory with subdirectories and ti

I have several directories with several subdirectories and files in them. I need to make a list of all these directories that is constructed in a way such that every first-level directory is listed next to the date and time of the latest created/modified file within it. ...
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How to format time since xxx e.g. “4 minutes ago” similar to Stack Exchange sites

...answered Jul 5 '10 at 7:45 Sky SandersSky Sanders 32k55 gold badges6161 silver badges8686 bronze badges ...
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MySQL connection not working: 2002 No such file or directory

I'm trying to set up WordPress. I have Apache and MySQL running, and the accounts and database are all set up. I tried to make a simple connection: ...
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Is floating point math broken?

...is like this. In most programming languages, it is based on the IEEE 754 standard. The crux of the problem is that numbers are represented in this format as a whole number times a power of two; rational numbers (such as 0.1, which is 1/10) whose denominator is not a power of two cannot be exactly re...
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How do I delete rows in a data frame?

... The key idea is you form a set of the rows you want to remove, and keep the complement of that set. In R, the complement of a set is given by the '-' operator. So, assuming the data.frame is called myData: myData[-c(2, 4, 6), ] # notice the - Of course, don't forget to "reassign" ...