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Check if a method exists
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answered Apr 28 '10 at 20:26
kennytmkennytm
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check if directory exists and delete in one command unix
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Dominic MitchellDominic Mitchell
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unix - head AND tail of file
Say you have a txt file, what is the command to view the top 10 lines and bottom 10 lines of file simultaneously?
20 Answer...
Does the ternary operator exist in R?
... %?% rnorm(5) %:% month.abb
## [1] 0.05363141 -0.42434567 -0.20000319 1.31049766 -0.31761248
FALSE %?% rnorm(5) %:% month.abb
## [1] "Jan" "Feb" "Mar" "Apr" "May" "Jun" "Jul" "Aug" "Sep" "Oct" "Nov" "Dec"
# or, more generally
condition %?% value1 %:% value2
It actually works if you define the op...
Why not use Double or Float to represent currency?
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1028
Because floats and doubles cannot accurately represent the base 10 multiples that we use for ...
Apache Spark: map vs mapPartitions?
... so.
– Nicholas White
Jan 18 '14 at 10:52
If you look at the source -- github.com/apache/incubator-spark/blob/… and ...
Create table in SQLite only if it doesn't exist already
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answered Nov 4 '10 at 15:06
David WoleverDavid Wolever
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How do I update if exists, insert if not (AKA “upsert” or “merge”) in MySQL?
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10
Yeah, I believe SQL Server's equivalent is called MERGE. In general, the concept is often referred to as "UPSERT".
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How does the Brainfuck Hello World actually work?
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+100
1. Basics
To understand Brainfuck you must imagine infinite array of cells initialized by 0 each.
...[0][0][0][0][0]...
When bra...
What does `kill -0 $pid` in a shell script do?
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answered Jun 13 '12 at 10:16
dwalterdwalter
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