I'm new to programming and I'm using Dart for a “introduction to programming“ course.
I'd like to write a code to validate if a text has only letter and space. I've found this for validate spaces.
function validate() {
var field = document.getElementById("myField");
if (field.value.replace(/ /g, "").length == 0) {
alert("Please enter some data (not spaces!)");
}
}
Thanks in advance, also I would need to write a string variable with sentences of different lengths and a function that finds the longest sentence. Any pointers?
[^a-z ] matches anything that is not a lowercase letter or space. caseSensitive: false makes it not match upper case either.
RegExp exp = new RegExp(r"[^a-z ]", caseSensitive: false);
print(exp.allMatches("this is valid").length == 0);
print(exp.allMatches("ThIs Is VaLiD").length == 0);
print(exp.allMatches("Th1s 1s NOT val1d").length == 0);
You can use exp.allMatches("string").length to find the number of characters that are not alpha or whitespace. so you can use:
if (exp.allMatches(field.value).length > 0) {
alert("Please enter some data (not spaces!)");
}
Related
if my string is lets say "Alfa1234Beta"
how can I convert all the number in to "_"
for example "Alfa1234Beta"
will be "Alfa____Beta"
Going with the Regex approach pointed out by others is possibly OK for your scenario. Mind you however, that Regex sometimes tend to be overused. A hand rolled approach could be like this:
static string ReplaceDigits(string str)
{
StringBuilder sb = null;
for (int i = 0; i < str.Length; i++)
{
if (Char.IsDigit(str[i]))
{
if (sb == null)
{
// Seen a digit, allocate StringBuilder, copy non-digits we might have skipped over so far.
sb = new StringBuilder();
if (i > 0)
{
sb.Append(str, 0, i);
}
}
// Replace current character (a digit)
sb.Append('_');
}
else
{
if (sb != null)
{
// Seen some digits (being replaced) already. Collect non-digits as well.
sb.Append(str[i]);
}
}
}
if (sb != null)
{
return sb.ToString();
}
return str;
}
It is more light weight than Regex and only allocates when there is actually something to do (replace). So, go ahead use the Regex version if you like. If you figure out during profiling that is too heavy weight, you can use something like the above. YMMV
You can run for loop on the string and then use the following method to replace numbers with _
if (!System.Text.RegularExpressions.Regex.IsMatch(i, "^[0-9]*$"))
Here variable i is the character in the for loop .
You can use this:
var s = "Alfa1234Beta";
var s2 = System.Text.RegularExpressions.Regex.Replace(s, "[0-9]", "_");
s2 now contains "Alfa____Beta".
Explanation: the regex [0-9] matches any digit from 0 to 9 (inclusive). The Regex.Replace then replaces all matched characters with an "_".
EDIT
And if you want it a bit shorter AND also match non-latin digits, use \d as a regex:
var s = "Alfa1234Beta๓"; // ๓ is "Thai digit three"
var s2 = System.Text.RegularExpressions.Regex.Replace(s, #"\d", "_");
s2 now contains "Alfa____Beta_".
I have an Array of strings:
private var phrase:Array = ["You will be given a series of questions like this:\n2 + 2 =\n(click or press ENTER to continue)","You can use the Keyboard or Mouse\nto deliver the answer\n\"ENTER\" locks it in.\n(click or press ENTER to continue)","\nClick Here\n to start."];
I have a conditional later in the script to see if the phrase[0] is equal to the instructText.text, so I put a "test" directly after the assignment as below:
instructText.text = phrase[0];
if (instructText.text == phrase[0]) {
trace("phrase zero");
}
else {
trace("nottttttttt");
}
//OUTPUT: nottttttttt
I've tried various combinations of phrase[0] as String and String(phrase[0]), but haven't had any luck.
What am I missing?
Turns out that the text property of the TextField class converts the "Line Feed" characters (the "\n", ASCII code of 1010=A16) to the character of "Carriage Return" (the ASCII code of 1310=D16).
So, you need a LF to CR conversion (or vise-versa) to make a homogeneous comparison of what is stored in the property against what you have in the array element:
function replaceLFwithCR(s:String):String {
return s.replace(/\n/g, String.fromCharCode(13));
}
if (instructText.text == replaceCRwithLF(phrase[0])) {
trace("They are equal :)");
}
else {
trace("They are NOT equal :(");
}
// Output: They are equal :)
P.S. To get the code of a character, you may utilize the charCodeAt() method of the String class:
trace("\n".charCodeAt(0)); // 10
I like to find all words in a List string equal input word, but 2 characters has variation. I like to find all words equal:
xxxV1xxx;
xxxV2xxx;
xxxV3xxx;...
I do not care if the word include V1, V2, V3; but has to have the same characters before and after.
Use mystring.StartsWith("xxx") && mystring.EndsWith("xxx")
Here is an example:
string[] str = { "xxxv1xxx", "xxxV2xxx", "xxxv3xxx", "xxv4xx", "xxV5xxx"};
foreach (string s in str)
{
if( s.StartsWith("xxx") && s.EndsWith("xxx"))
Console.WriteLine(s); //do whatever you want here
}
Fiddle: https://dotnetfiddle.net/STnyWE
I'm stuck on a task of trying to print words that contain only lowercase letters a-z. I have already stripped out an inputted string if it contains any number 0-9 and if it contains an Uppercase letter:
String[] textParts;
textParts = text.Split(delimChars);
for (int i = 0; i < textParts.Length; i++) //adds s to words list and checks for capitals
{
String s = textParts[i];
bool valid = true;
foreach (char c in textParts[i])
{
if (char.IsUpper(c))
{
valid = false;
break;
}
if (c >= '0' && c <= '9')
{
valid = false;
break;
}
if (char.IsPunctuation(c))
{
valid = false;
break;
}
}
if (valid) pageIn.words.Add(s);
This is my code so far. The last part I'm trying to check to see if a word contains any punctuation (it's not working) is there an easier way I could do this and how could I get the last part of my code to work?
P.S. I'm not that comfortable with using Regex.
Many Thanks,
Ellie
Without regex, you can use LINQ (might be less performant)
bool isOnlyLower = s.Count(c => Char.IsLower(c)) == s.Length;
Count will retrieve the number of char that are in lower in the following string. If it match the string's length, string is composed only of lowercase letters.
An alternative would be to check if there's any UpperCase :
bool isOnlyLower = !s.Any(c => Char.IsUpper(c));
var regex = new Regex("^[a-z]+$");
if (!regex.IsMatch(input))
{
// is't not only lower case letters, remove input
}
I'm not sure whether I get your question right, but shouldn't the following work?
for (int i = 0; i < textParts.Length; i++) //adds s to words list and checks for capitals
{
String s = textParts[i];
if(s.Equals(s.ToLower()))
{
// string is all lower
}
}
I'm building a short quiz where the user needs to input the meaning of an acronym.
This means I need to compare a long string (usually a sentence) typed in by the user with an acronym.
I have a feeling I'm not doing it right. For my testing I'm copy-pasting the correct answer to make sure the spelling is correct however I keep getting the feedback that the answer is incorrect.
My question is, am I comparing correctly?
Here's my code:
var arrQuestions:Array = [["LOL","Laughing Out Loud"], ["OMG", "Oh My God"], ["BTW", "By The Way"]];
var i:Number=0;
function setup():void {
quiztext_txt.text = arrQuestions[i][0];
trace(quiztext_txt.text);
trace(arrQuestions[i][1]);
check_btn.addEventListener(MouseEvent.CLICK, clickHandler);
}//End of Setup()
setup();
function clickHandler(event:MouseEvent):void {
var givenString:String;
var inputString:String;
inputString = userinput_txt.text;
givenString = arrQuestions[i][1];
if (inputString == givenString) {
feedback_txt.text = "Correct!";
} else {
feedback_txt.text = "Wrong!";
}
}
Is there any whitespace before/after the user input? Is the value of i changing in between?
else
{
//what does it trace?
trace("given answer: " + inputString + "\ncorrect answer: " + givenString);
feedback_txt.text = "Wrong!";
}
try clearing the text field in your setup function like so:
function setup():void
{
userinput_txt.text = "";
quiztext_txt.text = arrQuestions[i][0];
trace(quiztext_txt.text);
trace(arrQuestions[i][1]);
check_btn.addEventListener(MouseEvent.CLICK, clickHandler);
}//End of Setup()
For any kind of string matching I would strongly recommend looking into regular expressions (RegExp). In the regular expression written below I am matching each word, then I say [ ]+ which means "at least one or more spaces", then at the end of the expression I use /gi to say that the expression is case insensitive. In the code above if I type the phrase in lowercase its not going to match, a quick fix for this would be to use this if(inputString.toLowerCase() == givenString.toLowerCase()) which would catch this. Heres the regexp example:
// testString could easily equal myTextField.text
var testString:String = "lauGHing OuT loUD";
// you could store each one in an array, as you were before
var regEx:RegExp = /laughing[ ]+out[ ]+loud/gi
trace( regEx.test( testString ) ); //returns true,test() returns a Boolean
Hope this helps.