I have a UITextField and I need to check, as the user types, if the text they have entered in the textfield so far matches a specific pattern.
More specifically, I need the text to match the pattern ####-##-## where # is any digit 0-9 and - is a dash (note that this is NOT a phone number or email). For example, the entry 1990-12-09 matches, 1990:12:09 does not match and 1990-12 DOES match because it has not yet violated the pattern (even though the text does not yet completely match the pattern).
How should I approach this? Ideally I would not have to hard code in a series of if statements .
The difficulty is that I want to check if the text in the textfield matches this pattern, as the user types. I don't want to just check it at the end.
I'm thinking that regular expressions are probably the way, but I'm not experienced enough at them to know if they hold the solution.
You could set the keyboard type to myTextField.keyboardType = UIKeyboardTypeNumberPad that why you are limiting the type of input.
Then this post should help answer your formatting question: UITextField format in xx-xx-xxx
Related
So I am trying to make a password validator in Scratch where it asks the user to input an answer and then it puts the answer through some criterias and then outputs if it is a valid password or not. The criterias are:
Has at least 8 characters,
Has at least one uppercase letter,
Has at least one lowercase letter,
Has at least one number,
Has at least one special character,
Must contain less than 18 characters.
I tried to make a list first with all the different characters and check if the password contained them, but it doesn't actually work. I looked all over the internet for help on this but no one seems to have done it. The Scratch Wiki does have some stuff about case sensitivity but I haven't really been able to implement it. I really need help and I have been trying for a while now. Thanks.
If you just check if the password contains the list, it will only work if it has every single character of the list in order. If you want to make sure it contains each check, you're probably going to have to make a system that checks each letter for every check, which is a little complex.
Check if <lowercase letter/whatever check> contains(letter(text reading #) of (password))
If it passes this check, continue to the next check and set text reading # to 1. Otherwise, change text reading # by 1.
I assume you'll know how to code this properly, but I just partially phrased in the way a normal human would.
This will repeat until either it reaches the end of the password or it passes the check. it will then do this again, but for a different check. It's hard to explain in text, and this is my first answer, but I hope it helps.
You have to use the operators "contains", "length of" and > operators, from the end of the class. Combine "contains", "or" and "and".
I'm working on a translator that will take English language text (as user input into a UITextView) and (with a button press) replace specific words with alternatives. I have both the English words in scope plus their alternatives in separate Arrays (englishArray and alternativeArray), indexed correspondingly.
My challenge is finding an algorithm that will allow me to identify a word in the input text (a UITextView) ignoring characters like <",.()>, lookup the word in englishArray (case insensitive), locate the corresponding word in alternativeArray and then use that word in place of the original - writing it back to the UITextView.
Any help greatly appreciated.
NB. I have created a Category extending the NSArray functionality with a indexOfCaseInsensitiveString method that ignores case when doing an indexOfObject type lookup if that helps.
Tony.
I think that using an NSScanner would be best to parse the string into separate words which you could then pass to your indexOfCaseInsensitiveString method. scanCharactersFromSet:intoString: using a set of all the characters you want to ignore, including whitespace and newline characters should get you to the start of a word, and then you could use scanUpToCharactersFromSet:intoString: using the same set to scan to the end of the word. Using scanLocation at the beginning and end of each scan should allow you to get the range of that word, so if you find a match in your array, you will know where in your string to make the replacement.
Thanks for your suggestion. It's working with one exception.
I want to capture all punctuation so I can recreate the original input but with the substituted words. Even though I have a 'space' in my Character Set, the scanner is not putting the spaces into the 'intoString'. Other characters I specify in the Character Set such as '(' and ';' are represented in the 'intoString'.
Net is that when I recreate the input, it's perfect except that I get individual words running into each other.
UPDATE: I fixed that issue by including:
[theScanner setCharactersToBeSkipped:nil];
Thanks again.
I'd like to create a regular expression such that when I compare the a string against an array of strings, matches are returned with the regex ignoring certain characters.
Here's one example. Consider the following array of names:
{
"Andy O'Brien",
"Bob O'Brian",
"Jim OBrien",
"Larry Oberlin"
}
If a user enters "ob", I'd like the app to apply a regex predicate to the array and all of the names in the above array would match (e.g. the ' is ignored).
I know I can run the match twice, first against each name and second against each name with the ignored chars stripped from the string. I'd rather this by done by a single regex so I don't need two passes.
Is this possible? This is for an iOS app and I'm using NSPredicate.
EDIT: clarification on use
From the initial answers I realized I wasn't clear. The example above is a specific one. I need a general solution where the array of names is a large array with diverse names and the string I am matching against is entered by the user. So I can't hard code the regex like [o]'?[b].
Also, I know how to do case-insensitive searches so don't need the answer to focus on that. Just need a solution to ignore the chars I don't want to match against.
Since you have discarded all the answers showing the ways it can be done, you are left with the answer:
NO, this cannot be done. Regex does not have an option to 'ignore' characters. Your only options are to modify the regex to match them, or to do a pass on your source text to get rid of the characters you want to ignore and then match against that. (Of course, then you may have the problem of correlating your 'cleaned' text with the actual source text.)
If I understand correctly, you want a way to match the characters "ob" 1) regardless of capitalization, and 2) regardless of whether there is an apostrophe in between them. That should be easy enough.
1) Use a case-insensitivity modifier, or use a regexp that specifies that the capital and lowercase version of the letter are both acceptable: [Oo][Bb]
2) Use the ? modifier to indicate that a character may be present either one or zero times. o'?b will match both "o'b" and "ob". If you want to include other characters that may or may not be present, you can group them with the apostrophe. For example, o['-~]?b will match "ob", "o'b", "o-b", and "o~b".
So the complete answer would be [Oo]'?[Bb].
Update: The OP asked for a solution that would cause the given character to be ignored in an arbitrary search string. You can do this by inserting '? after every character of the search string. For example, if you were given the search string oleary, you'd transform it into o'?l'?e'?a'?r'?y'?. Foolproof, though probably not optimal for performance. Note that this would match "o'leary" but also "o'lea'r'y'" if that's a concern.
In this particular case, just throw the set of characters into the middle of the regex as optional. This works specifically because you have only two characters in your match string, otherwise the regex might get a bit verbose. For example, match case-insensitive against:
o[']*b
You can add more characters to that character class in the middle to ignore them. Note that the * matches any number of characters (so O'''Brien will match) - for a single instance, change to ?:
o[']?b
You can make particular characters optional with a question mark, which means that it will match whether they're there or not, e.g:
/o\'?b/
Would match all of the above, add .+ to either side to match all other characters, and a space to denote the start of the surname:
/.+? o\'?b.+/
And use the case-insensitivity modifier to make it match regardless of capitalisation.
I have an instance of NSTextField, e.g. someTextField, for which I will use the number formatter to limit the input to numbers only.
The problem comes with the localization combined with the specific keyboard layouts used.
I would like to allow both the, say, American and European users to enter their localized decimal separators. As you all know, in the USA that would be . and for the good part of Europe that would be , (and similar with the thousands separator, etc. but let's put that to the side for now).
So I wrote the following task:
[numberFormatter setLocale:[NSLocale currentLocale]]; for the instance of the NSNumberFormatter.
Problems occurs when the user who has , set as a decimal separator AND US keyboard layout switched on (fairly common here in Europe) presses the decimal separator key on the numeric keyboard. With the US keyboard layout on, that would give him the . as the decimal separator but at the same time it'll be ignored in the someTextField because of the localized settings system-wide. So, if you want to type 1/2 using numeric keyboard only, you'll type 0.5 (US keyboard layout) in the text field and it would be read by the system as 0 because it recognizes only , as decimal separator. This is how the program currently is working and I would like to improve it in this regard.
I would like to allow user to type in the . in the someTextField and for the system to recognize it as a decimal separator just like it would ,. This kind of behavior can be seen in Apple's own Calculator application. If you type . on the numeric keyboard it'll appear as , immediately on the screen (for all conditions as described previously).
Question is: is it possible for me to achieve this using an instance of NSNumberFormatter? If not, is it possible to set on-the-fly conversion of the numerical keyboard decimal separator key output to the decimal separator set system-wide? Or perhaps you have some other suggestions?
Thanks.
I don't have a specific answer to your question, but I'd say the right approach is not to muck about with the NSNumberFormatter at all and concentrate on trying to change the characters generated by the keyboard.
The default locale for number formatters is usually the system's default locale as set by the user in the internationalization settings. If you change that behaviour programmatically for UI elements, you are effectively telling the user "I know better than you how you want to input numbers". Arrogance of that sort on the part of the developer never gets them good marks with respect to UI design.
In fact, you could apply the same argument to remapping the dot button on the numeric keypad. How do you know that the user hasn't set US keyboard layout because it allows them to get a dot from that key? Maybe they consider it more important to be able to type the thousands separator from the keypad than the decimal separator. I'm not saying you shouldn't implement your feature, just make sure that the user has control over when it is enabled or disabled.
Anyway, you probably want to override the keyDown event on the control. More info here.
Take a look at the UITextFieldDelegate protocol. It allows your textfield to ask its delegate if it should accept a character which the user just typed. The apropriate method would be textField:shouldChangeCharactersInRange:replacementString. If the character in question is , or . just let the delegate append the properly localized decimal separator "manually" and return NO.
I'm not quite sure if this will work if the text field is set to number mode, maybe the input is being filtered before the delegate method is called - leading to the method not being called if the "wrong" separator has been filtered out previously. If so, you might want to consider leaving the text field in alphanumerical mode and use the delegate method again to filter out anything that is not numbers or separators. However, in this case you should make sure the user is not allowed to type more then one decimal separator - either ignore the surplus ones or remove the first one and accept the new one.
I am creating a program and I need to validate my text boxes. For the program the user needs to put in a phrase. But I am not sure how to make sure that the user actually entered in a phrase, the phrase isn't (ex.) skldkfdl, or that there isn't a space.
Strings in Java
You could do a String.Trim() to get rid of trailing whitespaces first...
then do a String.IndexOf(" ") to check for a space.
If the function returns -1, it means there is no space in the string.
Running on the assumption that you're using VB.Net - Add an event handler for the event where you want to validate the text, such as when a "Submit" button is clicked. You may want to use a CancelEventHandler, so that you can cancel the click.
In the event handler, if you're looking for just simple validation, you can use if-statements to check some simple conditions, such as if you just want to check "if input.equals(password)".
Look here for an example of using CancelEventHandler
If you're looking for some more complex validation, you'll want to use regular expressions.
This page might help get you started
Checking to see if something is "a phrase", as in, proper English, would be very difficult. You would need to make sure that all of the words are in the dictionary, and then you would need to check for proper grammar, which is incredibly complex, given English grammar rules. You may want to simplify your approach, depending on your problem. For example, maybe just check that no weird characters are used, that there is more than one space, and that each word contains a vowel.