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Coding Practices which enable the compiler/optimizer to make a faster program
...act.
Expect to be disappointed and to have to work very hard indeed for small performance improvements. Modern compilers for mature languages such as Fortran and C are very, very good. If you read an account of a 'trick' to get better performance out of code, bear in mind that the compiler writer...
Troubleshooting “Illegal mix of collations” error in mysql
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This is generally caused by comparing two strings of incompatible collation or by attempting to select data of different collation into a combined column.
The clause COLLATE allows you to specify the collation used in the query.
For exa...
Installing Java 7 on Ubuntu
to install java I have always used the classic way from the terminal.
I would like to install java manually.
I placed the folder of the JDK on the desk and I set environment variables (PATH, CLASSPATH and JAVA_HOME).
From the terminal, if I type java -version I get printed
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Using numpy to build an array of all combinations of two arrays
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It should be noted that meshgrid only works for smaller range sets, I have a large one and I get error: ValueError: maximum supported dimension for an ndarray is 32, found 69
– mikkom
Oct 20 '19 at 6:54
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Calculating a directory's size using Python?
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This walks all sub-directories; summing file sizes:
import os
def get_size(start_path = '.'):
total_size = 0
for dirpath, dirnames, filenames in os.walk(start_path):
for f in filenames:
fp = os.path.join(di...
Variable interpolation in the shell
I have a variable called filepath=/tmp/name .
3 Answers
3
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How to reshape data from long to wide format
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The reshape comments and similar argument names aren't all that helpful. However, I have found that for long to wide, you need to provide data = your data.frame, idvar = the variable that identifies your groups, v.names = the variables that will become multiple columns in wide f...
Why shouldn't I use mysql_* functions in PHP?
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The MySQL extension:
Is not under active development
Is officially deprecated as of PHP 5.5 (released June 2013).
Has been removed entirely as of PHP 7.0 (released December 2015)
This means that as of 31 Dec 2018 it does not exist in any supported version of PHP. If you are using a ve...
How to sort a list of objects based on an attribute of the objects?
...is a need to sort by multiple fields, it could be achieved by consecutive calls to sort(), because python is using stable sort algorithm.
– zzz777
Feb 23 at 14:41
add a commen...
Mailto links do nothing in Chrome but work in Firefox?
...omputer. I know at work, it will run thunderbird; if they have outlook installed it may run outlook, etc. Personally, it did not run gmail by default, I had to set it up that way.
– kennypu
Jul 14 '13 at 1:55
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