I would like to compare four UITextFields' text property to make sure they are not the same. Ie:
tbx1.text = "hello"
tbx2.text = "goodbye"
tbx3.text = "goodnight"
tbx4.text = "hello"
should return a false but
tbx1.text = "hello"
tbx2.text = "goodbye"
tbx3.text = "goodnight"
tbx4.text = "good morning"
should return a true.
I know I could use a long and complicated if statement but I'm hoping there is a better way
One possible solution is to add all Strings to a Set and check the count of the set. If it is 4, all textfields had a different value, if it is less than 4, you had duplicates.
You can even generalise it to work with a different number of text fields as well. You just add all textfields' text property to an array, create a Set from the array then compare the number of elements in the two collections.
let textFieldValues = [tbx1.text!, tbx2.text!, tbx3.text!, tbx4.text!]
let textFieldSet = Set(textFieldValues)
if textFieldSet.count == textFieldValues.count {
print("No duplicates")
} else {
print("Some duplicates")
}
Related
i want to get an element from a list of string and get the position of a char in this list by using linq ?
Example :
List<string> lines = new List<string> { "TOTO=1", "TATA=2", "TUTU=3"}
I want to extract the value 1 from TOTO in the list
here is the begin of my code
var value= lines.ToList().Single(x =>x.Contains("TOTO=")).ToString().Trim();
How to continue this code to extract 1 ?
Add this :
value = value[(value.LastIndexOf('=') + 1)..];
Using LINQ you can do this:
List<string> lines = new List<string> { "TOTO=1", "TATA=2", "TUTU=3" };
int value = lines
.Select(line => line.Split('='))
.Where(parts => parts[0] == "TOTO")
.Select(parts => int.Parse(parts[1]))
.Single();
If you always expect each item in that list to be in the proper format then this should work, otherwise you'd need to add some validation.
Similar to What #jtate proposed, Some minor enhancements can help.
int value = lines
.Select(line => line.Split(new []{ '=' }, StringSplitOptions.RemoveEmptyEntries))
.Where(parts => string.Equals(parts[0], "TOTO", StringComparison.InvariantCultureIgnoreCase))
.Select(parts => int.Parse(parts[1]))
.SingleOrDefault();
SingleOrDefault - If you don't find any elements matching your constraints, Single() would thow an exception. Here, SingleOrDefault would return 0;
String.Equals - would take care of any upper lowere or any culture related problems.
StringSplitOptions.RemoveEmptyEntries - would limit some unecessary iterations and improve performance.
Also see if you need int.TryParse instead of int.Prase. All these checks would help cover edges cases in production
Does Kotlin provide a mutation function to split a list when a specific predicate is true?
In the following example the list should be split when the element is a ..
The result should be of the type List<List<String>>.
// input list
val list = listOf(
"This is", "the", "first sentence", ".",
"And", "now there is", "a second", "one", ".",
"Nice", "."
)
// the following should be the result of the transformation
listOf(
listOf("This is", "the", "first sentence"),
listOf("And", "now there is", "a second", "one"),
listOf("Nice")
)
I need something like list.splitWhen { it == "." }
Does Kotlin provide a mutation function to split a list when a
specific predicate is true?
The closest one I have heard of is partition(), however I don't think it will work in your case.
I have made and have briefly tested 3 higher order extension functions, which gives the same expected output.
Solution 1: Straightforward approach
inline fun List<String>.splitWhen(predicate: (String)->Boolean):List<List<String>> {
val list = mutableListOf<MutableList<String>>()
var needNewList = false
forEach {
string->
if(!predicate(string)){
if(needNewList||list.isEmpty()){
list.add(mutableListOf(string))
needNewList= false
}
else {
list.last().add(string)
}
}
else {
/* When a delimiter is found */
needNewList = true
}
}
return list
}
Solution 2: Pair based approach
inline fun List<String>.splitWhen(predicate: (String)->Boolean):List<List<String>> {
val list = mutableListOf<List<String>>()
withIndex()
.filter { indexedValue -> predicate(indexedValue.value) || indexedValue.index==0 || indexedValue.index==size-1} // Just getting the delimiters with their index; Include 0 and last -- so to not ignore it while pairing later on
.zipWithNext() // zip the IndexValue with the adjacent one so to later remove continuous delimiters; Example: Indices : 0,1,2,5,7 -> (0,1),(1,2),(2,5),(5,7)
.filter { pair-> pair.first.index + 1 != pair.second.index } // Getting rid of continuous delimiters; Example: (".",".") will be removed, where "." is the delimiter
.forEach{pair->
val startIndex = if(predicate(pair.first.value)) pair.first.index+1 else pair.first.index // Trying to not consider delimiters
val endIndex = if(!predicate(pair.second.value) && pair.second.index==size-1) pair.second.index+1 else pair.second.index // subList() endIndex is exclusive
list.add(subList(startIndex,endIndex)) // Adding the relevant sub-list
}
return list
}
Solution 3: Check next value if delimiter found approach
inline fun List<String>.splitWhen(predicate: (String)-> Boolean):List<List<String>> =
foldIndexed(mutableListOf<MutableList<String>>(),{index, list, string->
when {
predicate(string) -> if(index<size-1 && !predicate(get(index+1))) list.add(mutableListOf()) // Adds a new List within the output List; To prevent continuous delimiters -- !predicate(get(index+1))
list.isNotEmpty() -> list.last().add(string) // Just adding it to lastly added sub-list, as the string is not a delimiter
else -> list.add(mutableListOf(string)) // Happens for the first String
}
list})
Simply call list.splitWhen{it=="delimiter"}. Solution 3 looks more syntactic sugar. Apart from it, you can do some performance test to check which one performs well.
Note: I have done some brief tests which you can have a look via Kotlin Playground or via Github gist.
I have items in a cms which have a 6-digit number.
The user can filter these item, via a input field,
by start typing a number.
const list = document.querySelector('#filter-wrap');
const searchBar = document.forms['search-kelim'].querySelector('input');
searchBar.addEventListener('keyup', function(e){
const term = e.target.value.toLowerCase();
const kelims = list.getElementsByClassName('filter-item');
Array.from(kelims).forEach(function(kelim){
let number = kelim.firstElementChild.textContent;
if(number.toLowerCase().indexOf(term) != -1 ){
console.log("Valid");
} else {
console.log("Invalid");
}
});
});
This is working, but it filters no matter where the digit
is occurring within the 6-digit number.
Aim is, it should only filter the first 3 starting digits, already starting with the first digit.
Meaning, if the user types 2, only the items starting with 2 are shown,
if the user then types 1, only the items starting with 21 are shown.
(the same for the third digit, typing 214 matches only the items starting with 214)
instead of indexof i tried with regex, but cannot get it to work:
var re = new RegExp("^[0-9]+$");
if (re.test(term)) {
console.log("Valid");
} else {
console.log("Invalid");
}
also tried these regex:
var re = new RegExp("^[0-9]");
var re = new RegExp("^\d{3}[0-9]");
var re = new RegExp("/[0-9]{1}[0-9]{1}[0-9]{1}/");
i also tried with match but also no luck, (different syntax?)
UPDATE:
here are two codepens for better understanding:
Filter with indexof, working but for first 3 digits.
https://codepen.io/hhentschel/pen/LYNWKeK
Filter with Regex, i tried all different answers, which came up so far.
https://codepen.io/hhentschel/pen/yLOMmbw
Your number variables all start with a line break. You may easily check that if you add console.log("'"+number+"': number") in the code.
To fix the regex approach, you just need to trim the incoming strings:
var re = new RegExp("^"+term);
if (re.test(number.trim())) { // <-- HERE!
kelim.classList.add("block");
kelim.classList.remove("hide");
} else {
kelim.classList.add("hide");
kelim.classList.remove("block");
}
Just check whether the Index is 0:
if(number.toLowerCase().indexOf(term) == 0){
console.log("Valid");
} else {
console.log("Invalid");
}
So you know that the term is at the beginning of the number.
But if you want to use regex, you have to build a new pattern every time:
var re = new RegExp("^"+term);
if (re.test(number)) {
console.log("Valid");
} else {
console.log("Invalid");
}
I am using regexpi to find a string in a phrase. But I also encountered with something different which I never intended.
Let's say the words I need to find are anandalak and nandaki.
str1 = {'anandalak'};
str2 = {'nanda'};
button = {'nanda'};
Both of the following return me logical 1:
~cellfun('isempty',regexpi(str1,button))
~cellfun('isempty',regexpi(str2,button))
How can I avoid this? I need logical 0 in first case and logical 1 in the second.
You probably need to use the word-boundaries(\<\>) in order to get the match which you require.
You may try:
str1 = {'anandalak'}
str2 = {'nanda'}
button = {'\<nanda\>'} % Notice this
~cellfun(#isempty,regexpi(str1,button)) % Returns ans = 0 No match
~cellfun(#isempty,regexpi(str2,button)) % Return ans = 1 Exact match
You can find the sample run result of the above implementation in here.
i have validating a clothes size field, and want it to accept only numbers and specific "words" like S, M, XL, XXL etc. But i am unsure how to add the words to the pattern. For example, i want it to match something like "2, 5, 23, S, XXXL" which are valid sizes, but not random combinations of letters like "2X3, SLX"
Ok since people are not suggesting regexp solutions i guess i should say that this is part of a larger method of validation which uses regexp. For convenience and code consistency i want to do this with regexp.
Thanks
If they're a known set of values, I am not sure a regex is the best way to do it. But here is one regex that is basically a brute-force match of your values, each with a \b (word boundary) anchor
\b2\b|\b5\b|\b23\b|\bXXXL\b|\bXL\b|\bM\b|\bS\b
Sorry for not giving you a straight answer. regexp might be overkill in your case. A solution without it could, depending on your needs, be more maintainable.
I don't know which language you use so I will just pick one randomly. You could treat it as a piece of pseudo code.
In PHP:
function isValidSize($size) {
$validSizeTags = array("S", "M", "XL", "XXL");
$minimumSize = 2;
$maximumSize = 23;
if(ctype_digit(strval($size))) { // explanation for not using is_numeric/is_int below
if($size >= $minimumSize && $size <= $maxiumSize) {
return true;
}
} else if(in_array($size, $validSizeTags)) {
return true;
} else {
return false;
}
}
$size = "XS";
$isValid = isValidSize($size); // true
$size = 23;
$isValid = isValidSize($size); // true
$size = "23";
$isValid = isValidSize($size); // true, is_int would return false here
$size = 50;
$isValid = isValidSize($size); // false
$size = 15.5;
$isValid = isValidSize($size); // false, is_numeric would return true here
$size = "diadjsa";
$isValid = isValidSize($size); // false
(The reason for using ctype_digit(strval($size)) instead of is_int or is_numeric is that the first one will only return true for real integers, not strings like "15". And the second one will return true for all numeric values not just integers. ctype_digit will however return true for strings containing numeric characters, but return false for integers. So we convert the value to a string using strval before sending it to ctype_digits. Welcome to the world of PHP.)
With this logic in place you can easily inject validSizeTags, maximumSize and minimumSize from a configuration file or a database where you store all valid sizes for this specific product. That would get much messier using regular expressions.
Here is an example in JavaScript:
var patt = /^(?:\d{1,2}|X{0,3}[SML])$/i;
patt.test("2"); // true
patt.test("23"); // true
patt.test("XXXL"); // true
patt.test("S"); // true
patt.test("SLX"); // false
Use Array Membership Instead of Regular Expressions
Some problems are easier to deal with by using a different approach to representing your data. While regular expressions can be powerful, you might be better off with an array membership test if you are primarily interested in well-defined fixed values. For example, using Ruby:
sizes = %w[2 5 23 S XXXL].map(&:upcase)
size = 'XXXL'
sizes.include? size.to_s.upcase # => true
size = 'XL'
sizes.include? size.to_s.upcase # => false
seeing as it is being harder than i had thought, i am thinking to store the individual matched values in an array and match those individually against accepted values. i will use something like
[0-9]+|s|m|l|xl|xxl
and store the matches in the array
then i will check each array element against [0-9]+ and s|m|l|xl|xxl and if it matches any of these, it's valid. maybe there is a better way but i can't dwell on this for too long
thanks for your help
This will accept the alternatives one or more times, separated by whitespace or punctuation. It should be easy enough to expand the separator character class if you think you need to.
^([Xx]{0,3}[SsMmLl]|[0-9]+)([ ,:;-]+([Xx]{0,3}[SsMmLl]))*$
If you can interpolate the accepted pattern into a string before using it as a regex, you can reduce the code duplication.
This is a regular egrep pattern. Regex dialects differ between languages, so you might need to tweak something in order to adapt it to your language of choice (PHP? It's good form to include this information in the question).