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Why is lazy evaluation useful?
...ges let you reason about function definitions using equational reasoning.
foo x = x + 3
Unfortunately in a non-lazy setting, more statements fail to return than in a lazy setting, so this is less useful in languages like ML. But in a lazy language you can safely reason about equality.
Secondly, ...
PHP expresses two different strings to be the same [duplicate]
...e, typeof operator always returns a string, so you could just use
typeof foo == 'string' instead of typeof foo === 'string' with no harm.
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compareTo() vs. equals()
...
A difference is that "foo".equals((String)null) returns false while "foo".compareTo((String)null) == 0 throws a NullPointerException. So they are not always interchangeable even for Strings.
...
What is the difference between Gemfile and Gemfile.lock in Ruby on Rails
...last digit in the used gem can be "greater than" the given version. E.g., foo ~> a.b.c.d means any version of foo is fine as long as it's still a.b.c.{something} where {something} >= d. See also related question
– michael
Feb 10 '13 at 0:32
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How can I determine the current line number in JavaScript?
...some marks.
Here is a quick example (yes, it's messed a little).
function foo()
{
alert(line(1));
var a;
var b;
alert(line(2));
}
foo();
function line(mark)
{
var token = 'line\\(' + mark + '\\)';
var m = line.caller.toString().match(
new Re...
How do you check in python whether a string contains only numbers?
... I had no idea that method existed. I've always done try: assert str(int(foo)) == foo; except (AssertionError,ValueError): #handle and it felt ugly as sin. Thanks!
– Adam Smith
Jan 27 '14 at 18:23
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Is there a performance difference between i++ and ++i in C?
...uld indeed be slower since with ++it you can just return the final value.
Foo Foo::operator++()
{
Foo oldFoo = *this; // copy existing value - could be slow
// yadda yadda, do increment
return oldFoo;
}
Another difference is that with ++i you have the option of returning a reference instead...
jQuery get value of select onChange
...ith script you need to pass a reference to the current element:
onselect="foo(this);"
and then:
function foo(element) {
// $(element).val() will give you what you are looking for
}
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Why does cURL return error “(23) Failed writing body”?
...ious program is finished writing the whole page.
In curl "url" | grep -qs foo, as soon as grep has what it wants it will close the read stream from curl. cURL doesn't expect this and emits the "Failed writing body" error.
A workaround is to pipe the stream through an intermediary program that alwa...
How can I print variable and string on same line in Python?
...print statement separates the items by a single space:
>>> print "foo","bar","spam"
foo bar spam
or better use string formatting:
print "If there was a birth every 7 seconds, there would be: {} births".format(births)
String formatting is much more powerful and allows you to do some other ...