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| extension String { | |
| func trimBackTo(boundary: Character) -> String { | |
| if isEmpty {return ""} | |
| if self[endIndex.predecessor()] == boundary { return "" } | |
| return characters.split(boundary).map(String.init).last! | |
| } | |
| func trimUpTo(boundary: Character) -> String { | |
| if isEmpty { return "" } | |
| if self[startIndex] == boundary {return String(self[startIndex])} | |
| return characters.split(boundary, maxSplit: 1, allowEmptySlices: false).map(String.init).first! | |
| } | |
| } |
erica
commented
Dec 28, 2015
extension String {
/// Retake on "lastPathComponent" and "pathExtension"
/// but a little more general in behavior
///
/// - Author: aciidb
func snipBackTo(boundary: Character) -> String {
if isEmpty || self[endIndex.predecessor()] == boundary { return "" }
return characters.split(boundary).map(String.init).last ?? self
}
/// Snip forward to boundary
///
/// - Author: aciidb
func snipUpTo(boundary: Character) -> String {
if isEmpty || self[startIndex] == boundary {return ""}
return characters.split(boundary, maxSplit: 1, allowEmptySlices: false).map(String.init).first ?? self
}
/// Trim back from end
func trimBackTo(boundary: Character) -> String {
if isEmpty {return ""}
if self[endIndex.predecessor()] == boundary {return self[startIndex...endIndex.predecessor().predecessor()]}
let last = characters.split(boundary).map(String.init).last ?? ""
if last == self {return self}
return String(characters.dropLast(last.characters.count + 1)) ?? self
}
/// Trim forward to boundary
func trimUpTo(boundary: Character) -> String {
if isEmpty { return "" }
if self[startIndex] == boundary { return self[startIndex.successor()...endIndex.predecessor()] }
let first = characters.split(boundary).map(String.init).first ?? ""
if first == self {return self}
return String(characters.dropFirst(first.characters.count + 1)) ?? self
}
}
var path = "/Users/ericasadun/Desktop/feefs.txt/filename.fext"
path.snipBackTo("Z") == path
path.snipBackTo("/") == "filename.fext"
path.snipBackTo(".") == "fext"
path.snipUpTo("Z") == path
path.snipUpTo("/") == ""
path.snipUpTo(".") == "/Users/ericasadun/Desktop/feefs"
path.trimBackTo("Z") == path
path.trimBackTo("/") == "/Users/ericasadun/Desktop/feefs.txt"
path.trimBackTo(".") == "/Users/ericasadun/Desktop/feefs.txt/filename"
path.trimBackTo("t") == "/Users/ericasadun/Desktop/feefs.txt/filename.fex"
path.trimUpTo("Z") == path
path.trimUpTo("/") == "Users/ericasadun/Desktop/feefs.txt/filename.fext"
path.trimUpTo(".") == "txt/filename.fext"
path = "x"
path.snipBackTo("Z") == "x"
path.snipUpTo("Z") == "x"
path.trimUpTo("Z") == "x"
path.trimBackTo("Z") == "x"
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