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A variable modified inside a while loop is not remembered
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@AvinashYadav The problem isn't really related to while loop or for loop; rather the use of subshell i.e., in cmd1 | cmd2, cmd2 is in a subshell. So if a for loop is executed in a subshell, the unexpected/problematic behaviour will be exhibited.
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Easiest way to check for an index or a key in an array?
... associative array)
[ ${array[key]+abc} ] && echo "exists"
Basically what ${array[key]+abc} does is
if array[key] is set, return abc
if array[key] is not set, return nothing
References:
See Parameter Expansion in Bash manual and the little note
if the colon is omitted, the ope...
Sending HTML email using Python
...multiple messages? Should I quit everytime I send the message or send them all (in a for loop) and then quit once and for all?
– xpanta
May 9 '12 at 9:58
1
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Overriding a JavaScript function while referencing the original
...tioned in the comments, be sure to include the () at the end. You want to call the outer function and store the result (one of the two inner functions) in a, not store the outer function itself in a.
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What does the explicit keyword mean?
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The compiler is allowed to make one implicit conversion to resolve the parameters to a function. What this means is that the compiler can use constructors callable with a single parameter to convert from one type to another in order to get t...
How are booleans formatted in Strings in Python?
...he object as transparantly as possible for python. For example, print(str("foo")) merely prints foo on a new line. print(repr("foo")) however prints 'foo' on a new line, including the quotes, since that's what you need to type in the python interpreter to get the corresponding object to the argument...
What's the (hidden) cost of Scala's lazy val?
...he bitmap indicates it is necessary.
Using:
class Something {
lazy val foo = getFoo
def getFoo = "foo!"
}
produces sample bytecode:
0 aload_0 [this]
1 getfield blevins.example.Something.bitmap$0 : int [15]
4 iconst_1
5 iand
6 iconst_0
7 if_icmpne 48
10 aload_0 [this]
11 dup
12...
Class does not implement its superclass's required members
... I updated to Xcode 6 beta 5 today and noticed I received errors in nearly all of my subclasses of Apple's classes.
4 Answe...
MongoDB atomic “findOrCreate”: findOne, insert if nonexistent, but do not update
...: { _id: "some potentially existing id" },
update: {
$setOnInsert: { foo: "bar" }
},
new: true, // return new doc if one is upserted
upsert: true // insert the document if it does not exist
})
As $setOnInsert only affects documents being inserted, if an existing document is found, no...
Removing event listener which was added with bind
...uation was this:
A new function reference is created after .bind() is called!
See Does bind() change the function reference? | How to set permanently?
So, to add or remove it, assign the reference to a variable:
var x = this.myListener.bind(this);
Toolbox.addListener(window, 'scroll', x);
To...