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Performance of FOR vs FOREACH in PHP
...g out on top (surprise, surprise).
//make a nicely random array
$aHash1 = range( 0, 999999 );
$aHash2 = range( 0, 999999 );
shuffle( $aHash1 );
shuffle( $aHash2 );
$aHash = array_combine( $aHash1, $aHash2 );
$start1 = microtime(true);
foreach($aHash as $key=>$val) $aHash[$key]++;
$end1 = micro...
How to modify list entries during for loop?
...r loop variant, looks cleaner to me than one with enumerate():
for idx in range(len(list)):
list[idx]=... # set a new value
# some other code which doesn't let you use a list comprehension
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Regular Expression for alphanumeric and underscores
...ntation at the above links states that \w will "Match any character in the range 0 - 9, A - Z and a - z (equivalent of POSIX [:alnum:])", I have not found this to be true. Not with grep -P anyway. You need to explicitly include the underscore if you use [:alnum:] but not if you use \w. You can't bea...
Hash Map in Python
...class HashMap:
def __init__(self):
self.store = [None for _ in range(16)]
def get(self, key):
index = hash(key) & 15
if self.store[index] is None:
return None
n = self.store[index]
while True:
if n.key == key:
...
Filter dataframe rows if value in column is in a set list of values [duplicate]
...
you can also use ranges by using:
b = df[(df['a'] > 1) & (df['a'] < 5)]
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I have 2 dates in PHP, how can I run a foreach loop to go through all of those days?
...
Copy from php.net sample for inclusive range:
$begin = new DateTime( '2012-08-01' );
$end = new DateTime( '2012-08-31' );
$end = $end->modify( '+1 day' );
$interval = new DateInterval('P1D');
$daterange = new DatePeriod($begin, $interval ,$end);
foreach($da...
How do I check that multiple keys are in a dict in a single pass?
...andom import randint as R;d=dict((str(R(0,1000000)),R(0,1000000)) for i in range(D));q=dict((str(R(0,1000000)),R(0,1000000)) for i in range(Q));print("looking for %s items in %s"%(len(q),len(d)))'''
>>> Timer('set(q) <= set(d)','D=1000000;Q=100;'+setup).timeit(1)
looking for 100 items i...
What is a regular expression for a MAC Address?
...is not valid in most flavors, except for BRE/ERE, which supports character range collation. However, support for character range collation varies among implementation, so the result may vary.
– nhahtdh
May 6 '15 at 3:14
...
Generate list of all possible permutations of a string
..., Python example:
def nextPermutation(perm):
k0 = None
for i in range(len(perm)-1):
if perm[i]<perm[i+1]:
k0=i
if k0 == None:
return None
l0 = k0+1
for i in range(k0+1, len(perm)):
if perm[k0] < perm[i]:
l0 = i
perm[k...
Example use of “continue” statement in Python?
...
import random
for i in range(20):
x = random.randint(-5,5)
if x == 0: continue
print 1/x
continue is an extremely important control statement. The above code indicates a typical application, where the result of a division by z...