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How to properly override clone method?
...ken.
Josh Bloch on Design - Copy Constructor versus Cloning
If you've read the item about cloning in my book, especially if you read between the lines, you will know that I think clone is deeply broken. [...] It's a shame that Cloneable is broken, but it happens.
You may read more discussion ...
How can I remove the first line of a text file using bash/sed script?
... slower than sed, though. I wonder how they managed that; tail should just read a file line by line while sed does pretty complex operations involving interpreting a script, applying regular expressions and the like.
Note: You may be tempted to use
# THIS WILL GIVE YOU AN EMPTY FILE!
tail -n +2 "$...
Excel “External table is not in the expected format.”
I'm trying to read an Excel (xlsx) file using the code shown below. I get an "External table is not in the expected format." error unless I have the file already open in Excel. In other words, I have to open the file in Excel first before I can read if from my C# program. The xlsx file is on a share...
When is it better to use String.Format vs string concatenation?
...as well.
With C# 6
String interpolation makes a lot of things simpler to read in C# 6. In this case, your second code becomes:
xlsSheet.Write($"C{rowIndex}", null, title);
which is probably the best option, IMO.
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What is an index in SQL?
... any index. This is a good start for troubleshooting performance problems. Read more here:
http://dev.mysql.com/doc/refman/5.0/en/explain.html
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What are the differences between B trees and B+ trees?
... the pointers in a single page of memory. We want to require only one disk read per leaf access, so we don't want to assign more than a page size of pointers to a leaf. If we fill a leaf with a page size of pointers, and then we want to add another pointer to this leaf, we create two children of thi...
What does it mean when MySQL is in the state “Sending data”?
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This is quite a misleading status. It should be called "reading and filtering data".
This means that MySQL has some data stored on the disk (or in memory) which is yet to be read and sent over. It may be the table itself, an index, a temporary table, a sorted output etc.
If you ...
How to handle AccessViolationException
...by your standard managed code. I won't get into the why's or how's here. Read this article about CSE's in the .NET 4.0 Framework:
http://msdn.microsoft.com/en-us/magazine/dd419661.aspx#id0070035
But there is hope. There are a few ways to get around this:
Recompile as a .NET 3.5 assembly and r...
Confused about Service vs Factory
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I like this... When i read the thousand lines of sentence from other blogger.. i only manage to understand factory. But i read this... i understand all 3.
– tsohtan
Dec 4 '15 at 10:24
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Warning message: In `…` : invalid factor level, NA generated
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If you are reading directly from CSV file then do like this.
myDataFrame <- read.csv("path/to/file.csv", header = TRUE, stringsAsFactors = FALSE)
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