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Haskell function composition (.) and function application ($) idioms: correct use
I have been reading Real World Haskell , and I am nearing the end, but a matter of style has been niggling at me to do with the (.) and ($) operators.
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How to open every file in a folder?
...wd()):
with open(os.path.join(os.cwd(), filename), 'r') as f: # open in readonly mode
# do your stuff
Glob
Or you can list only some files, depending on the file pattern using the glob module:
import glob
for filename in glob.glob('*.txt'):
with open(os.path.join(os.cwd(), filename),...
MySQL Insert into multiple tables? (Database normalization?)
...ver crashes). If you can live with "some have finished, others not", don't read on.
If however you decide "either all queries finish, or none finish - I do not want rows in some tables but no matching rows in others, I always want my database tables to be consistent", you need to wrap all statement...
Why would introducing useless MOV instructions speed up a tight loop in x86_64 assembly?
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You may want to read http://research.google.com/pubs/pub37077.html
TL;DR: randomly inserting nop instructions in programs can easily increase performance by 5% or more, and no, compilers cannot easily exploit this. It's usually a combinatio...
Difference between single and double square brackets in Bash
I'm reading bash examples about if but some examples are written with single square brackets:
6 Answers
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PHP - concatenate or directly insert variables in string
...uch a case (Variable interpolation), which I find easier to both write and read.
The result will be the same; and even if there are performance implications, those won't matter 1.
As a sidenote, so my answer is a bit more complete: the day you'll want to do something like this:
echo "Welcome $na...
When saving, how can you check if a field has changed?
...requires making alterations to your model, this one does not 3) as you can read in the comments on that answer, it has side-effects that can be potentially problematic, this solution does not
– Chris Pratt
Oct 31 '11 at 22:10
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Should I prefer pointers or references in member data?
...at it makes the code easier to write it's that it makes the code easier to read. With a reference as a data member you never have to wonder if it can be null at point of use. This means that you can look at code with less context required.
– Len Holgate
Jan 4 '...
SQL: How to properly check if a record exists
While reading some SQL Tuning-related documentation, I found this:
9 Answers
9
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What are the uses of the exec command in shell scripts? [closed]
...ere are some examples:
exec 3< thisfile # open "thisfile" for reading on file descriptor 3
exec 4> thatfile # open "thatfile" for writing on file descriptor 4
exec 8<> tother # open "tother" for reading and writing on fd 8
exec 6>> other # op...