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Clojure: cons (seq) vs. conj (list)
...guments to insert into a collection, while cons takes just one:
(conj '(1 2 3) 4 5 6)
; => (6 5 4 1 2 3)
(cons 4 5 6 '(1 2 3))
; => IllegalArgumentException due to wrong arity
Another difference is in the class of the return value:
(class (conj '(1 2 3) 4))
; => clojure.lang.Persistent...
Which equals operator (== vs ===) should be used in JavaScript comparisons?
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Time complexity of Sieve of Eratosthenes algorithm
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Your n/2 + n/3 + n/5 + … n/97 is not O(n), because the number of terms is not constant. [Edit after your edit: O(n2) is too loose an upper bound.] A loose upper-bound is n(1+1/2+1/3+1/4+1/5+1/6+…1/n) (sum of reciprocals of all n...
`from … import` vs `import .` [duplicate]
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246
It depends on how you want to access the import when you refer to it.
from urllib import requ...
Validate phone number with JavaScript
...ectly. It validates that the phone number is in one of these formats:
(123) 456-7890 or 123-456-7890
26 Answers
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What is the use of Enumerable.Zip extension method in Linq?
...ers= new string[] { "A", "B", "C", "D", "E" };
var numbers= new int[] { 1, 2, 3 };
var q = letters.Zip(numbers, (l, n) => l + n.ToString());
foreach (var s in q)
Console.WriteLine(s);
Ouput
A1
B2
C3
share
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Convert pandas dataframe to NumPy array
...taframe (df) to a numpy ndarray, use this code:
df.values
array([[nan, 0.2, nan],
[nan, nan, 0.5],
[nan, 0.2, 0.5],
[0.1, 0.2, nan],
[0.1, 0.2, 0.5],
[0.1, nan, 0.5],
[0.1, nan, nan]])
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Ruby: What is the easiest way to remove the first element from an array?
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"pop"ing the first element of an Array is called "shift" ("unshift"
being the operation of add...
Gmail Error :The SMTP server requires a secure connection or the client was not authenticated. The s
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25 Answers
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CPU Privilege Rings: Why rings 1 and 2 aren't used?
...of the modern protection model) only has a concept of privileged (ring 0,1,2) and unprivileged, the benefit to rings 1 and 2 were diminished greatly.
The intent by Intel in having rings 1 and 2 is for the OS to put device drivers at that level, so they are privileged, but somewhat separated from th...