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Filter data.frame rows by a logical condition
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To select rows according to one 'cell_type' (e.g. 'hesc'), use ==:
expr[expr$cell_type == "hesc", ]
To select rows according to two or more different 'cell_type', (e.g. either 'hesc' or 'bj fibroblast'), use %in%:
expr[expr$cell_type %in% c("hesc", "bj fibrobl...
Clean ways to write multiple 'for' loops
For an array with multiple dimensions, we usually need to write a for loop for each of its dimensions. For example:
16 An...
Can C++ code be valid in both C++03 and C++11 but do different things?
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The answer is a definite yes. On the plus side there is:
Code that previously implicitly copied objects will now implicitly move them when possible.
On the negative side, several examples are listed in the appendix C of the standard. Even though th...
How can I generate Unix timestamps?
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In Linux or MacOS you can use:
date +%s
where
+%s, seconds since 1970-01-01 00:00:00 UTC. (GNU Coreutils 8.24 Date manual)
Example output now 1454000043.
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LINQ OrderBy versus ThenBy
Can anyone explain what the difference is between:
4 Answers
4
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Saving images in Python at a very high quality
How can I save Python plots at very high quality?
5 Answers
5
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Is there a Python Library that contains a list of all the ascii characters?
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The string constants may be what you want. (docs)
>>> import string
>>> string.ascii_uppercase
'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
If you want all printable characters:
>>> string.printable
'0123456789abcdefghijklmnopqrstu...
Purpose of Unions in C and C++
I have used unions earlier comfortably; today I was alarmed when I read this post and came to know that this code
15 Ans...
Android Get Current timestamp?
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The solution is :
Long tsLong = System.currentTimeMillis()/1000;
String ts = tsLong.toString();
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OOP vs Functional Programming vs Procedural [closed]
What are the differences between these programming paradigms, and are they better suited to particular problems or do any use-cases favour one over the others?
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