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IN vs OR in the SQL WHERE Clause
...')
WHERE foo = 'a' OR foo = 'b' OR foo = 'c'
According to the manual for MySQL if the values are constant IN sorts the list and then uses a binary search. I would imagine that OR evaluates them one by one in no particular order. So IN is faster in some circumstances.
The best way to know is to p...
Non-recursive depth first search algorithm
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DFS:
list nodes_to_visit = {root};
while( nodes_to_visit isn't empty ) {
currentnode = nodes_to_visit.take_first();
nodes_to_visit.prepend( currentnode.children );
//do something
}
BFS:
list nodes_to_visit = {root};
while( nodes_to_visit isn't ...
My Git repository is in the wrong root directory. Can I move it? (../ instead of ./)
...or so ago I ran the command in the directory one directory higher than the root of my project.
9 Answers
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os.walk without digging into directories below
... os.path.isdir(some_dir)
num_sep = some_dir.count(os.path.sep)
for root, dirs, files in os.walk(some_dir):
yield root, dirs, files
num_sep_this = root.count(os.path.sep)
if num_sep + level <= num_sep_this:
del dirs[:]
It works just like os.walk, but y...
How can you represent inheritance in a database?
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Does other DBs support INHERITS besides PostgreSQL ? MySQL for example ?
– giannis christofakis
Mar 11 '16 at 9:00
1
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How do I list all cron jobs for all users?
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You would have to run this as root, but:
for user in $(cut -f1 -d: /etc/passwd); do crontab -u $user -l; done
will loop over each user name listing out their crontab. The crontabs are owned by the respective users so you won't be able to see another u...
List files by last edited date
...ort | cut -f 2- -d ' '
The result looks a lot like ls -l:
-rw-r--r-- 1 root root 3892 08/11/2009 11:03:36 /usr/share/man/man1/xmllint.1.gz
-rw-r--r-- 1 root root 22946 08/13/2009 11:59:20 /usr/share/man/man1/curl.1.gz
-rw-r--r-- 1 root root 728 08/17/2009 12:0...
Sass combining parent using ampersand (&) with type selectors
...his has been possible since Sass 3.3.0.rc.1 (Maptastic Maple).
The @at-root directive causes one or more rules to be emitted at the root of the document, rather than being nested beneath their parent selectors.
We can combine the @at-root directive along with interpolation #{} to arrive at the...
List directory tree structure in python?
...to do that with formatting:
import os
def list_files(startpath):
for root, dirs, files in os.walk(startpath):
level = root.replace(startpath, '').count(os.sep)
indent = ' ' * 4 * (level)
print('{}{}/'.format(indent, os.path.basename(root)))
subindent = ' ' * 4 *...
Recursive sub folder search and return files in a list python
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You should be using the dirpath which you call root. The dirnames are supplied so you can prune it if there are folders that you don't wish os.walk to recurse into.
import os
result = [os.path.join(dp, f) for dp, dn, filenames in os.walk(PATH) for f in filenames if os.pa...