Suppose I have a string "10.9.1.1", I want to get substring "10.9". How can I achieve this?
So far I have the following:
var str = "10.9.1.1"
let range = str.rangeOfString(".",options: .RegularExpressionSearch)!
let rangeOfDecimal = Range(start:str.startIndex,end:range.endIndex)
var subStr = str.subStringWithRange(rangeOfDecimal)
But this will only return 10.
Actually your code returns "1" only, because "." in a regular
expression pattern matches any character.
The correct pattern would be
\d+ one ore more digits
\. a literal dot
\d+ one or more digits
In a Swift string, you have to escape the backslashes as "\\":
let str = "10.9.1.1"
if let range = str.rangeOfString("\\d+\\.\\d+",options: .RegularExpressionSearch) {
let subStr = str.substringWithRange(range)
println(subStr) // "10.9"
}
Related
Need to remove part of the string based on brackets.
For ex:
let str = "My Account (_1234)"
I wanted to remove inside brackets (_1234) and the result should be string My Account
Expected Output:
My Account
How can we achieve this with regex format or else using swift default class,need support on this.
Tried with separatedBy but it splits string into array but that is not the expected output.
str.components(separatedBy: "(")
Use replacingOccurrences(…)
let result = str.replacingOccurrences(of: #"\(.*\)"#,
with: "",
options: .regularExpression)
.trimmingCharacters(in: .whitespaces))
Regex ist not necessary. Just get the range of ( and extract the substring up to the lower bound of the range
let str = "My Account (_1234)"
if let range = str.range(of: " (") {
let account = String(str[..<range.lowerBound])
print(account)
}
Objective-C code:
NSString *str = #"hi";
NSString *strDigit = #"1934"; (or #"193" may be a 3 digit or 4 digit value)
[dayText appendFormat:#"%#%4s,str,[strDigit UTF8String]];
The Objective-C code handles the output string with current alignment when it appears with 3 or 4 digits as output. It is correctly aligning to left and doesn't matter how much digits it is. Any one know how to handle this in Swift?
In Swift I tried with below code and the string is not adjusting the alignment according to the number of digits.
textForTrip += "\(str) \(String(format:"%4s", (strDigit.utf8))"
The %s format expects a pointer to a (NULL-terminated) C string
as argument, that can be obtained with the withCString method.
This would produce the same output as your Objective-C code:
let str = "Hi"
let strDigit = "193"
let text = strDigit.withCString {
String(format: "%#%4s", str, $0)
}
print(text)
It becomes easier if you store the number as integer instead of a
string:
let str = "Hi"
let number = 934
let text = String(format: "%#%4d", str, number)
print(text)
Try this below approach, that might help you
let strDigit = "\("1934".utf8)" //(or #"193" may be a 3 digit or 4 digit value)
var dayText = "Hello, good morning."
dayText += "\(strDigit.prefix(3))"
I have Strings with the form string \ string example
"some sting with random length\233"
I want to deletes the last \ and get the value after it, so the result will be
"some sting with random length"
"233"
I tried this code but it's not working
let regex = try! NSRegularExpression(pattern: "\\\s*(\\S[^,]*)$")
if let match = regex.firstMatch(in: string, range: string.nsRange) {
let result = string.substring(with: match.rangeAt(1))
}
You did not correctly adapt the pattern from How to get substring after last occurrence of character in string: Swift IOS to your case. Both instances of the comma must be replaced by a backslash,
and that must be "double-escaped":
let regex = try! NSRegularExpression(pattern: "\\\\\\s*(\\S[^\\\\]*)$")
(once be interpreted as a literal backslash in the regex pattern, and
once more in the definition of a Swift string literal).
However, a simpler solution is to find the last occurrence of the
backslash and extract the suffix from that position:
let string = "some sting with random length\\233"
let separator = "\\" // A single(!) backslash
if let r = string.range(of: separator, options: .backwards) {
let prefix = string.substring(to: r.lowerBound)
let suffix = string.substring(from: r.upperBound)
print(prefix) // some sting with random length
print(suffix) // 233
}
Update for Swift 4:
if let r = string.range(of: separator, options: .backwards) {
let prefix = string[..<r.lowerBound]
let suffix = string[r.upperBound...]
print(prefix) // some sting with random length
print(suffix) // 233
}
prefix and suffix are a String.SubSequence, which can be used
in many places instead of a String. If necessary, create a real
string:
let prefix = String(string[..<r.lowerBound])
let suffix = String(string[r.upperBound...])
You could do this with regex, but I think this solution is better:
yourString.components(separatedBy: "\\").last!
It splits the string with \ as the separator and gets the last split.
Sorry,I'm new of swift. I want to calculate the target char in string.But I don't know how to do.Have any good suggestion to me?Thanks.
let string = "hello\nNice to meet you.\nMy name is Leo.\n" //I want to get 3
If you simply want a count of newline characters then you can use a filter on the string's characters:
let string = "hello\nNice to meet you.\nMy name is Leo.\n"
let count = string.characters.filter { $0 == "\n" }.count
print(count)
This outputs 3 as expected.
An alternative is to split the lines with the components(separatedBy method:
let string = "hello\nNice to meet you.\nMy name is Leo.\n"
let lineCounter = string.components(separatedBy: "\n").count - 1
or more versatile to consider all kinds of newline characters
let lineCounter = string.components(separatedBy: CharacterSet.newlines).count - 1
Due to the trailing newline character the result is 4. To ignore a trailing new line you have to decrement the result.
I have a string: "Hey #username that's funny". For a given string, how can I search the string to return all ranges of string with first character # and last character to get the username?
I suppose I can get all indexes of # and for each, get the substringToIndex of the next space character, but wondering if there's an easier way.
If your username can contain only letters and numbers, you can use regular expression for that:
let s = "Hey #username123 that's funny"
if let r = s.rangeOfString("#\\w+", options: NSStringCompareOptions.RegularExpressionSearch) {
let name = s.substringWithRange(r) // #username123"
}
#Vladimir's answer is correct, but if you're trying to find multiple occurrences of "username", this should also work:
let s = "Hey #username123 that's funny"
let ranges: [NSRange]
do {
// Create the regular expression.
let regex = try NSRegularExpression(pattern: "#\\w+", options: [])
// Use the regular expression to get an array of NSTextCheckingResult.
// Use map to extract the range from each result.
ranges = regex.matchesInString(s, options: [], range: NSMakeRange(0, s.characters.count)).map {$0.range}
}
catch {
// There was a problem creating the regular expression
ranges = []
}
for range in ranges {
print((s as NSString).substringWithRange(range))
}