I have this string:
Some text: $ 12.3 9
I want to get as a result:
12.39
I have found examples on how to keep only numbers, but here I am wanting to keep the decimal point "."
What's a good way to do this in Swift?
This should work (it's a general approach to filtering on a set of characters) :
[EDIT] simplified and adjusted to Swift3
[EDIT] adjusted to Swift4
let text = "$ 123 . 34 .876"
let decimals = Set("0123456789.")
var filtered = String( text.filter{decimals.contains($0)} )
If you need to ignore anything past the second decimal point add this :
filtered = filtered.components(separatedBy:".") // separate on decimal point
.prefix(2) // only keep first two parts
.joined(separator:".") // put parts back together
Easiest and simplest reusable way: you can use this regex replacement option. This replaces all characters except 0 to 9 and dot (.) .
let yourString = "$123. 34"
//pattern says except digits and dot.
let pattern = "[^0-9.]"
do {
let regex = try NSRegularExpression(pattern: pattern, options: NSRegularExpressionOptions.CaseInsensitive)
//replace all not required characters with empty string ""
let string_With_Just_Numbers_You_Need = regex.stringByReplacingMatchesInString(yourString, options: NSMatchingOptions.WithTransparentBounds, range: NSMakeRange(0, yourString.characters.count), withTemplate: "")
//your number converted to Double
let convertedToDouble = Double(string_With_Just_Numbers_You_Need)
} catch {
print("Cant convert")
}
One possible solution to the question follows below. If you're working with text fields and currency, however, I suggest you take a look at the thread Leo Dabus linked to.
extension String {
func filterByString(myFilter: String) -> String {
return String(self.characters.filter {
myFilter.containsString(String($0))
})
}
}
var a = "$ 12.3 9"
let myFilter = "0123456789.$"
print(a.filterByString(myFilter)) // $12.39
Related
i need to take only the integer from a string like this "Critical: 3\r\n" , note that the value change everytime so i can't search for "3", i need to search for a generic int.
Thanks.
Many ways to do it. There are already some answers. Here is one more approach:
let s = "Critical: 3\r\n";
let s_res = s.split(":").collect::<Vec<&str>>()[1].trim();
println!("s_res = {s_res:?}"); // "3"
In the above code s_res will be a string (&str). To convert that string to an integer, you can do something like this:
let n: isize = s_res.parse().expect("Failed to parse the integer!");
println!("n = {n}"); // 3
Note that, depending on your needs, you might want to add some extra validations/asserts, in case you expect the pattern might change (for example, the number of colons not to be 1, etc.).
Building on #AlexanderKrauze's comment the most common way to do so is using a regex, which lets you look for any pattern in a String:
let your_text = "Critical: 3\r\n";
let re = Regex::new(r"\d+").unwrap(); // matches any amount of consecutive digits
let result:Option<Match> = re.find(your_text);// returns the match
let number:u32 = result.map(|m| m.as_str().parse::<u32>().unwrap()).unwrap_or(0); // converts to int
print!("{}", number);
would be the code for that. Only one digit is r"\d".
More documentation is found here.
You can use chars to get an iterator over the chars of a string, and then apply filter on that iterator to filter out only digits(is_digit).
fn main() {
let my_str: String = "Critical: 3\r\n".to_owned();
let digits: String = my_str.chars().filter(|char| char.is_digit(10)).collect();
println!("{}", digits)
}
So I am learning Kotlin now, and I was trying to do a calculator where if we can give expression like 4+3 or 3*5 and we will get the answer so I was trying to split that input string and then find what operator is used and what are the operands.
var list = str.split("+","-","*","/" )
so how can i get the delimiter that is used to split that string too.
I'm afraid that split method doesn't have this feature. You would have to split the the string via separate split calls. And compare the outcome with original string. If the string wasn't split by given delimiter that outcome should be the same.
Eg. like this:
var str = "5+1"
var delimiters = arrayOf("+","-","*","/")
var found = "Not found"
for (delimiter in delimiters) {
var splited = str.split(delimiter)
if(splited[0] != str) {
found = delimiter
break
}
}
println(found)
I my app can read this string out of a QR Code, the amount of values differs per code
Example:
"<23><423><12><54>"
I would like to get each value which are separated by < & >
I thought of a loop which prints out each value. but im not really sure how to search for the values.
Thanks in advance
One possible solution:
let string = "<23><423><12><54>"
let nsString = string as NSString // (Works better with NSRegularExpression)
let regex = NSRegularExpression(pattern: "<(\\d+)>", options: nil, error: nil)!
regex.enumerateMatchesInString(nsString, options: nil, range: NSMakeRange(0, nsString.length)) {
(result, _, _) -> Void in
let code = nsString.substringWithRange(result.rangeAtIndex(1))
println(code)
}
"<(\\d+)>" is a regular expression pattern that matches one or more
digits enclosed in <...>, and the parentheses define a "capture group"
which is then extracted with result.rangeAtIndex(1).
I'm looking to find the last instance of a character in a string. Given the different way Swift deals with strings (ranges), I was hoping someone has run into this before as I can't seem to figure out the best way to deal with it.
The string I'd like to parse is similar to "http://imanimage_thatlooks_likethis_andmypixare_380.jpg". I need to parse the segment between the last "_" and the last ".". So the number 380. Each link is formatted this way, but the substring methodology for Swift is still a bit foreign to me, with the inclusion of different byte lengths.
Thanks in advance!
// regular expression to find substring between last "_" and last "."
let sourceStr = "abc_defg_hijk_lmn.xyz"
let regex = NSRegularExpression( pattern: "_([^_]*)\\.[^\\.]*$", options:nil, error:nil );
if let matchingResult = regex?.firstMatchInString( sourceStr, options: nil, range: NSMakeRange( 0, countElements( sourceStr ) ) ) {
let matchingRange = matchingResult.rangeAtIndex(1)
let matchingString = (sourceStr as NSString).substringWithRange( matchingRange )
}
I have a string, starting with a number, then a space, then a word of an unknown amount of letters, a space again, and then sometimes another piece of text (which may or may not contain more than one word).
EDIT: the last piece of text is sometimes left out (see example #2)
Using the methods mentioned in the comments, str:find(...) on #2 would return nil.
Example:
"(number) (text) [more text]"
1: "10 HELLO This is a string"
2: "88 BYE"
What I want is to split these strings into a table, inside a table containing more of these split strings, like this:
{
[(number)] = { [1] = (text), [2] = (more text) }
[10] = { [1] = "HELLO", [2] = "This is a string" }
}
I have tried several methods, but none of them give me the desired result.
One of the methods I tried, for example, was splitting the string on whitespaces. But that resulted in:
{
[10] = { [1] = "HELLO", [2] = "This", ... [4] = "string" }
}
Thanks in advance.
Using various Lua string patterns, achieving the desired result is quite easy.
For eg.
function CustomMatching( sVar )
local tReturn = {}
local _, _, iNumber, sWord, sRemain = sVar:find( "^(%d+)%s(%a+)%s(.+)" )
tReturn[tonumber(iNumber)] = { sWord, sRemain }
return tReturn
end
And to call it:
local sVar = "10 HELLO This is a string"
local tMyTable = CustomMatching( sVar )
In the find() method the pattern "^(%d+)%s(%a+)%s(.+)" means:
Find and store all digits(%d) until a space is encountered.
Find and store all letters(%a) until a space is encountered.
Find and store all characters until the end of string is reached.
EDIT
Changed tReturn[iNumber] to tReturn[tonumber(iNumber)] as per the discussion in comments.
You can use the string.match method with an appropriate pattern:
local n, w, str = ('10 HELLO This is a string'):match'^(%d+)%s+(%S+)%s+(.*)$'
your_table[tonumber(n)] = {w, str}