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Write a function that returns the longest palindrome in a given string
...ng "ABCDEFCBA".
Not that the string has "ABC" and "CBA" as its substring. If you reverse the original string, it will be "ABCFEDCBA". and the longest matching substring is "ABC" which is not a palindrome.
You may need to additionally check if this longest matching substring is actually a palindrom...
Remove all the elements that occur in one list from another
...es exactly what you want and stores the result in l3:
l3 = [x for x in l1 if x not in l2]
l3 will contain [1, 6].
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Should you always favor xrange() over range()?
...hon 3, range() does what xrange() used to do and xrange() does not exist. If you want to write code that will run on both Python 2 and Python 3, you can't use xrange().
range() can actually be faster in some cases - eg. if iterating over the same sequence multiple times. xrange() has to reconstruc...
Check if character is number?
...
You could use comparison operators to see if it is in the range of digit characters:
var c = justPrices[i].substr(commapos+2,1);
if (c >= '0' && c <= '9') {
// it is a number
} else {
// it isn't
}
...
Why '&&' and not '&'?
...at the evaluation is canceled as soon as the result is clear.
Example:
if(CanExecute() && CanSave())
{
}
If CanExecute returns false, the complete expression will be false, regardless of the return value of CanSave. Because of this, CanSave is not executed.
This is very handy in the f...
Is there a way to define a min and max value for EditText in Android?
...input = Integer.parseInt(dest.toString() + source.toString());
if (isInRange(min, max, input))
return null;
} catch (NumberFormatException nfe) { }
return "";
}
private boolean isInRange(int a, int b, int c) {
return b > a ? c >...
How to check if element has any children in Javascript?
...ve an element which I am grabbing via .getElementById () . How do I check if it has any children?
8 Answers
...
Cleaning `Inf` values from an R dataframe
...ame]])), j = .name,value =NA)))
Or using column numbers (possibly faster if there are a lot of columns):
for (j in 1:ncol(DT)) set(DT, which(is.infinite(DT[[j]])), j, NA)
Timings
# some `big(ish)` data
dat <- data.frame(a = rep(c(1,Inf), 1e6), b = rep(c(Inf,2), 1e6),
c = ...
Build tree array from flat array in javascript
... has :
id : a unique id,
parentId : the id of the parent node (which is 0 if the node is a root of the tree)
level : the level of depth in the tree
...
MySQL, Check if a column exists in a table with SQL
I am trying to write a query that will check if a specific table in MySQL has a specific column, and if not — create it. Otherwise do nothing. This is really an easy procedure in any enterprise-class database, yet MySQL seems to be an exception.
...