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Can't pickle when using multiprocessing Pool.map()
...r program to allow such methods to be pickled, registering it with the copy_reg standard library method.
For example, Steven Bethard's contribution to this thread (towards the end of the thread) shows one perfectly workable approach to allow method pickling/unpickling via copy_reg.
...
difference between variables inside and outside of __init__()
...
Variable set outside __init__ belong to the class. They're shared by all instances.
Variables created inside __init__ (and all other method functions) and prefaced with self. belong to the object instance.
...
How to save all the variables in the current python session?
...r work:
import shelve
T='Hiya'
val=[1,2,3]
filename='/tmp/shelve.out'
my_shelf = shelve.open(filename,'n') # 'n' for new
for key in dir():
try:
my_shelf[key] = globals()[key]
except TypeError:
#
# __builtins__, my_shelf, and imported modules can not be shelved.
...
Named routes _path vs _url
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_path helpers provide a site-root-relative path. You should probably use this most of the time.
_url helpers provide an absolute path, including protocol and server name. I've found that I mainly use these in emails when cre...
How to base64 encode image in linux bash / shell
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You need to use cat to get the contents of the file named 'DSC_0251.JPG', rather than the filename itself.
test="$(cat DSC_0251.JPG | base64)"
However, base64 can read from the file itself:
test=$( base64 DSC_0251.JPG )
...
How do I create a namespace package in Python?
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TL;DR:
On Python 3.3 you don't have to do anything, just don't put any __init__.py in your namespace package directories and it will just work. On pre-3.3, choose the pkgutil.extend_path() solution over the pkg_resources.declare_namespace() one, because it's future-proof and already compatible w...
Flatten nested dictionaries, compressing keys
...ng the dictionary at final step.
import collections
def flatten(d, parent_key='', sep='_'):
items = []
for k, v in d.items():
new_key = parent_key + sep + k if parent_key else k
if isinstance(v, collections.MutableMapping):
items.extend(flatten(v, new_key, sep=s...
Code Golf: Lasers
...amp;!ge,$s=$r+=99for<>;%d='>.^1<2v3'=~/./g;($r)=grep$d|=$d{$t{$_}},%t;
{$_=$t{$r+=(1,-99,-1,99)[$d^=3*/\\/+m</>]};/[\/\\ ]/&&redo}die/x/?true:false,$/
The first line loads the input into %t, a table of the board where $t{99*i+j} holds the character at row i,column j. Then...
Weighted random numbers
...er is less than that item's weight
Pseudo-code illustrating this:
int sum_of_weight = 0;
for(int i=0; i<num_choices; i++) {
sum_of_weight += choice_weight[i];
}
int rnd = random(sum_of_weight);
for(int i=0; i<num_choices; i++) {
if(rnd < choice_weight[i])
return i;
rnd -= choic...
How to use filter, map, and reduce in Python 3
...
@Breezer actually i**3 will call i.__pow__(3) and i*i*i i.__mul__(i).__mul__(i) (or something like that). With ints it doesn't matter but with numpy numbers/custom classes it might even produce different results.
– syntonym
...