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Slicing of a NumPy 2d array, or how do I extract an mxm submatrix from an nxn array (n>m)?
I want to slice a NumPy nxn array. I want to extract an arbitrary selection of m rows and columns of that array (i.e. without any pattern in the numbers of rows/columns), making it a new, mxm array. For this example let us say the array is 4x4 and I want to extract a 2x2 array from it.
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When should I use C++ private inheritance?
Unlike protected inheritance, C++ private inheritance found its way into mainstream C++ development. However, I still haven't found a good use for it.
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How to compare times in Python?
...to flip the acceptance to Pär Wieslander's answer (and generally should wait a few more minutes than you did :P), as it's a bit more specific to exactly what you asked.
– Roger Pate
Dec 2 '09 at 8:40
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SQLite add Primary Key
I created a table in Sqlite by using the CREATE TABLE AS syntax to create a table based on a SELECT statement. Now this table has no primary key but I would like to add one.
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Extract month and year from a zoo::yearmon object
...") ## Month, char, abbreviated
[1] "Mar"
> format(date1, "%Y") ## Year with century
[1] "2012"
> format(date1, "%m") ## numeric month
[1] "03"
These are returned as characters. Where appropriate, wrap in as.numeric() if you want the year or numeric month as a numeric variable, e.g.
> as....
str performance in python
...rt an object (in my case an integer) to a string is almost an order of magnitude slower than using string formatting.
2 Ans...
javac is not recognized as an internal or external command, operable program or batch file [closed]
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TL;DR
For experienced readers:
Find the Java path; it looks like this: C:\Program Files\Java\jdkxxxx\bin\
Start-menu search for "environment variable" to open the options dialog.
Examine PATH. Remove old Java paths.
Add the new Java path to PATH.
Edit JAVA_HOME.
Close and re-...
UnicodeDecodeError: 'utf8' codec can't decode byte 0xa5 in position 0: invalid start byte
...e error is because there is some non-ascii character in the dictionary and it can't be encoded/decoded. One simple way to avoid this error is to encode such strings with encode() function as follows (if a is the string with non-ascii character):
a.encode('utf-8').strip()
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Ruby capitalize every word first letter
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try this:
puts 'one TWO three foUR'.split.map(&:capitalize).join(' ')
#=> One Two Three Four
or
puts 'one TWO three foUR'.split.map(&:capitalize)*' '
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How to check if object (variable) is defined in R?
I'd like to check if some variable is defined in R - without getting an error. How can I do this?
6 Answers
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