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EC2 instance has no public DNS
A guy I work with gave me the EC2 credentials to log onto his EC2 console. I was not the one who set it up. Some of the instances show a public dns name and others have a blank public DNS. I want to be able to connect to the instances that have a blank public DNS. I have not been able to figure out ...
What is the difference between float and double?
...le has 2x the precision of float[1]. In general a double has 15 decimal digits of precision, while float has 7.
Here's how the number of digits are calculated:
double has 52 mantissa bits + 1 hidden bit: log(253)÷log(10) = 15.95 digits
float has 23 mantissa bits + 1 hidden bit: log(224)÷log(10) =...
Programmatically go back to the previous fragment in the backstack
Say I have an activity that has fragments added programmatically:
12 Answers
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Java compiler level does not match the version of the installed Java project facet
...ios Version, where my JRE Version is set to 1.6.
I have added Maven capabilities to the Web Application by clicking on Configure → Convert to Maven Project .
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Recover from git reset --hard?
Is there any way to recover uncommitted changes to the working directory from a git reset --hard HEAD ?
22 Answers
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Flatten list of lists [duplicate]
I'm having a problem with square brackets in Python. I wrote a code that produces the following output:
4 Answers
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How to execute PHP code from the command line?
...nt like if(function_exists("my_func")) echo 'function exists'; directly with the command line without having to use a seperate php file.
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\d is less efficient than [0-9]
...0123456789] in a regular expression rather than [0-9] or \d . I said it was probably more efficient to use a range or digit specifier than a character set.
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How to insert a text at the beginning of a file?
...e at the beginning of a file but that's not exactly what I want. I'll show it on a example
16 Answers
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How to merge dictionaries of dictionaries?
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this is actually quite tricky - particularly if you want a useful error message when things are inconsistent, while correctly accepting duplicate but consistent entries (something no other answer here does....)
assuming you don't have huge num...