I'm writing a function to replace substrings (what laguange doesn't have this, grr), and I am getting some strange characters in my ouput. I cannot figure out why.
string replaceSubstring(string input, string targetSubstring, string substitute, bool matchCase)
{
string result = input
Buffer b = create
b = input
int targetStartPos
int targetLength
while (findPlainText(result, targetSubstring, targetStartPos, targetLength, matchCase))
{
string prefixStr = b[0:targetStartPos - 1]
string suffixStr = b[targetStartPos + targetLength:]
b = prefixStr substitute suffixStr
result = tempStringOf(b)
}
delete b
return result
}
When running print replaceSubstring("Jake Lewis", "ake", "ack", false), I get an output of �*��*�is. This would appear to be some sort of encoding issue, but I am unclear on how this is happening, or how to fix it.
Try using stringOf() instead of tempStringOf(). Your processing is fine, but the result becomes invalid after deleting b.
Related
How can i outputs result between 2 specific characters in dart String
example
String myVlue = 'helloWorld';
wanted result is : anything between 'hel' and 'ld'
so the result is 'loWor'
Note : in my case the two specific characters are fixed and Unique
How can i tell dart to do that in best way .
thanks
You could define a regular expression to catch a group from your input:
void main() {
String myValue = 'helloWorld';
RegExp regExp = RegExp(r'hel(.*)ld');
String extract = regExp.firstMatch(myValue)![1]!;
print(extract); // loWor
}
Hi so i have a double seems like this
d1 = 12.106
and i need to show in to a string '12.130'
double num1 = double. parse((12.3404). toStringAsFixed(3));
well i expected to return "12.130" but it returned "12.13"
the thing i need a string "12.130" instead "12.13"
double num1 = double. parse((12.3404). toStringAsFixed(4));
so tried this one again but also failed
well then number must be shown 3 decimals even if the last is 0
where or what should i have to fix?
I understand you have the following variable:
double d = 12.130;
and now you want to convert it to a string with the following value: String s = "12.130"
This should work:
String res = d.toStringAsFixed(3) //"12.130"
I'm a beginner in dart.
void main() {
var abf = '+37.4054-122.0999/';
var abf2;
abf2 = abf.replaceAll("+"," ");
var abf1 = abf2.split(RegExp('(?=[+-])'));
print (abf1[0]);
print (abf1[1]);
}
The above code splits abf into two values for me
I want to remove the ending '/'. I tried many split methods using other variables but it's not removing the '/' even though its removing the '+'.
It's not really clear what you're trying to do with the split.
But if you're looking the remove the / this should work:
String number = '+37.4054-122.0999/';
number = number.replaceAll("/"," ");
You can create substring from this while you like to remove last element.
String abf = '+37.4054-122.0999/';
final result = abf.substring(0, abf.length - 1);
print(result);
Dart's List class has a built-in removeLast method. Maybe you can try to split the string and then removing the last element:
String str = "str";
String newStr = str.split(''). removeLast().join('');
How do I get the last n-characters in a string?
I've tried using:
var string = 'Dart is fun';
var newString = string.substring(-5);
But that does not seem to be correct
var newString = string.substring(string.length - 5);
Create an extension:
extension E on String {
String lastChars(int n) => substring(length - n);
}
Usage:
var source = 'Hello World';
var output = source.lastChars(5); // 'World'
While #Alexandre Ardhuin is correct, it is important to note that if the string has fewer than n characters, an exception will be raised:
Uncaught Error: RangeError: Value not in range: -5
It would behoove you to check the length before running it that way
String newString(String oldString, int n) {
if (oldString.length >= n) {
return oldString.substring(oldString.length - n)
} else {
// return whatever you want
}
}
While you're at it, you might also consider ensuring that the given string is not null.
oldString ??= '';
If you like one-liners, another options would be:
String newString = oldString.padLeft(n).substring(max(oldString.length - n, 0)).trim()
If you expect it to always return a string with length of n, you could pad it with whatever default value you want (.padLeft(n, '0')), or just leave off the trim().
At least, as of Dart SDK 2.8.1, that is the case. I know they are working on improving null safety and this might change in the future.
var newString = string.substring((string.length - 5).clamp(0, string.length));
note: I am using clamp in order to avoid Value Range Error. By that you are also immune to negative n-characters if that is somehow calculated.
In fact I wonder that dart does not have such clamp implemented within the substring method.
If you want to be null aware, just use:
var newString = string?.substring((string.length - 5).clamp(0, string.length));
I wrote my own solution to get any no of last n digits from a string of unknown length, for example the 5th to the last digit from an n digit string,
String bin='408 408 408 408 408 1888';// this is the your string
// this function is to remove space from the string and then reverse the
string, then convert it to a list
List reversed=bin.replaceAll(" ","").split('').reversed.toList();
//and then get the 0 to 4th digit meaning if you want to get say 6th to last digit, just pass 0,6 here and so on. This second reverse function, return the string to its initial arrangement
var list = reversed.sublist(0,4).reversed.toList();
var concatenate = StringBuffer();
// this function is to convert the list back to string
list.forEach((item){
concatenate.write(item);
});
print(concatenate);// concatenate is the string you need
I have asked a question before about this program, but it seems that not all problems are resolved. I am currently experiencing an error that states: "Cannot convert value of type 'String' to expected argument type '_Element' (aka 'Character') on the "guard let indexInWord" line:
guard let letterIndex = letters.indexOf(sender)
else { return }
let letter = letterArray[letterIndex]
guard let indexInWord = word.characters.indexOf(letter)
else {
print("no such letter in this word")
return
}
// since we have spaces between dashes, we need to calc index this way
let indexInDashedString = indexInWord * 2
var dashString = wordLabel.text
dashString[indexInDashedString] = letter
wordLabel.text = dashString
I tried converting the String 'letter' to Character but it only resulted in more errors. I was wondering how I can possibly convert String to argument type "_Element." Please help.
It is hard to treat a string like a list in swift, mostly because the String.characters is not a typical array. Running a for loop on that works, but if you are looking for a specific character given an index, it is a bit more difficult. What I like doing is adding this function to the string class.
extenstion String {
func getChars() -> [String] {
var chars:[String] = []
for char in characters {
chars.append(String(char))
}
return chars
}
}
I would use this to define a variable when you receive input, then check this instead of String.characters