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Category Archives: riddle
javascript speed test
Aside
given the following function:
function addInts(anArray){
var result = 0;
for (var i = 0; i < anArray.length; ++i){
if (anArray[i] < 21) {
result = result + anArray[i];
} else {
result = result + anArray[i] - 21;
}
}
return result;
}
what would you expect will run faster?
addInts(sortedArray); #sorted
addInts(unsortedArray); #unsorted
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javascript anagram detector
Aside
what’s the shortest anagram detector you know how to write, in javascript?
there must be a shorter way to do this. highlight below to see a solution.
var anagramDetector = function (x,y) {
if (x.length != y.length) return false;
var alpha_x = x.split("").sort().join("");
var alpha_y = y.split("").sort().join("");
for ( j = 0; j<y.length;++j) {
if (alpha_x[j] != alpha_y[j]) return false;
}
return true;
}
PS: there’s a cool method for solving this for a fixed alphabet, using primes
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detecting anagrams in python
Aside
what’s the shortest anagram detector you know how to write, in python?
this is one that keeps feeling like it should be a one liner (because it’s very similar to this one liner), but i suspect can’t be done in one line
highlight to see a solution.
def fn(x,y):
if len(x) != len(y):
return False
for i in x:
y = y.replace(i,'',1)
return not len(y) > 0
PS: there’s a cool method for solving this for a fixed alphabet, using primes
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javascript speed test
Aside
if you had to guess, which of the following two bits of javascript code would you say executes faster?
Exhibit A:
var keys = Object.keys(MyObj); //cloning the key array
var length = keys.length;
for (var i = 0; i < length; i++) {
var val = MyObj[keys[i]];
};
Exhibit B:
for (var key in MyObj) {
if (MyObj.hasOwnProperty(key)) { //hasOwnProperty is a native function
var val = MyObj[key];
}
}
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this is what things looked like last year in september, with an up to date version of chrome:
arrays (javascript)
Aside
how well do you know your arrays?
figure out what you think each line does, and then check yourself by running them in a console
test = [1,2,3] test test.length test.length = 5 test.length test
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riddle 11 (javascript)
Aside
javascript riddle
does null == false?
if (null) { console.log("null"); }
if (null == false) { console.log("null == false"); }
if (!null) { console.log("!null"); }
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riddle 10 (javascript)
Aside
javascript riddle #4
true or false?
['a','b'] < ['a','b'] ['a','b'] <= ['a','b'] ['a','b'] == ['a','c'] ['a','b'] >= ['a','c'] ['a','b'] > ['a','c'] ['a','b'] = ['a','b'] ['a','b'] == ['a','b'] ['a','b'] === ['a','b']
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riddle 9 (python)
Aside
python riddle
def fn():
x = "Who's on first"
def f(y):
return x+y
x = "What's on second"
return f("?")
print fn()
(ok, so this is more of a mnemonic to help me remember how python works)
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null vs. undefined (javascript)
Aside
how well do you know your “null”s and “undefined”s?
write down what you expect the result of each operation to be. run them in a javascript console (Chrome, Firefox/Firebug, Safari). compare, verify, contrast, and, for fun, give yourself a score out of “3/4 donut”.
// Equality
null == undefined
null === undefined
!null == !undefined
!null === !undefined
// addition and concatenation
null + ''
undefined + ''
null + 1
undefined + 1
// fun with enumerations
test = []; test.push(null); console.log(test)
test = []; test.push(undefined); console.log(test)
{null:2}
{undefined:2}
{a:null}
{a:undefined}
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ferretfarmer 