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Permission denied (publickey) when SSH Access to Amazon EC2 instance [closed]
I want to use my Amazon ec2 instance but faced the following error:
29 Answers
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How to set a Timer in Java?
How to set a Timer, say for 2 minutes, to try to connect to a Database then throw exception if there is any issue in connection?
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How do I merge a list of dicts into a single dict?
... d in L:
... result.update(d)
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>>> result
{'a':1,'c':1,'b':2,'d':2}
As a comprehension:
# Python >= 2.7
{k: v for d in L for k, v in d.items()}
# Python < 2.7
dict(pair for d in L for pair in d.items())
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Truncate number to two decimal places without rounding
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How do I delete rows in a data frame?
...he '-' operator.
So, assuming the data.frame is called myData:
myData[-c(2, 4, 6), ] # notice the -
Of course, don't forget to "reassign" myData if you wanted to drop those rows entirely---otherwise, R just prints the results.
myData <- myData[-c(2, 4, 6), ]
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How to use the 'sweep' function
...ation defined by FUN.
For instance, if you want to add 1 to the 1st row, 2 to the 2nd, etc. of the matrix you defined, you will do:
sweep (M, 1, c(1: 4), "+")
I frankly did not understand the definition in the R documentation either, I just learned by looking up examples.
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Why is parenthesis in print voluntary in Python 2.7?
In Python 2.7 both the following will do the same
4 Answers
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How do I get current date/time on the Windows command line in a suitable format for usage in a file/
Update: Now that it's 2016 I'd use PowerShell for this unless there's a really compelling backwards-compatible reason for it, particularly because of the regional settings issue with using date . See @npocmaka's https://stackoverflow.com/a/19799236/8479
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C# LINQ find duplicates in List
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edited Mar 28 '18 at 5:05
Vadim Ovchinnikov
9,91644 gold badges3939 silver badges6969 bronze badges
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If vs. Switch Speed
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answered Jan 14 '09 at 23:16
Konrad RudolphKonrad Rudolph
461k118118 gold badges863863 silver badges11101110 bronze badges
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