I have a method that detects urls in a string and returns me both the urls and the ranges where they can be found. Everything works perfectly until there are emojis on the string. For example:
"I'm gonna do this callenge as soon as I can swing again 😂😂😂\n http://youtu.be/SW_d3fGz1hk"
Because of the emojis, the url extracted from the text is http://youtu.be/SW_d3fGz1 instead of http://youtu.be/SW_d3fGz1hk. I figured that the easiest solution was to just replace the emojis on the string with whitespace characters (cause I need the range to be correct for some text styling stuff). Problem is, this is extremely hard to accomplish with Swift (most likely my abilities with the Swift String API is lacking).
I've been trying to do it like this but it seems that I cannot create a string from an array of unicode points:
var emojilessStringWithSubstitution: String {
let emojiRanges = [0x1F601...0x1F64F, 0x2702...0x27B0]
let emojiSet = Set(emojiRanges.flatten())
let codePoints: [UnicodeScalar] = self.unicodeScalars.map {
if emojiSet.contains(Int($0.value)) {
return UnicodeScalar(32)
}
return $0
}
return String(codePoints)
}
Am I approaching this problem the wrong way? Is replacing emojis the best solution here? If so, how can I do it?
You can use pattern matching (for emoji patterns) to filter out emoji characters from your String.
extension String {
var emojilessStringWithSubstitution: String {
let emojiPatterns = [UnicodeScalar(0x1F601)...UnicodeScalar(0x1F64F),
UnicodeScalar(0x2702)...UnicodeScalar(0x27B0)]
return self.unicodeScalars
.filter { ucScalar in !(emojiPatterns.contains{ $0 ~= ucScalar }) }
.reduce("") { $0 + String($1) }
}
}
/* example usage */
let str = "I'm gonna do this callenge as soon as I can swing again 😂😂😂\n http://youtu.be/SW_d3fGz1hk"
print(str.emojilessStringWithSubstitution)
/* I'm gonna do this callenge as soon as I can swing again
http://youtu.be/SW_d3fGz1hk */
Note that the above only makes use of the emoji intervals as presented in your question, and is in no way representative for all emojis, but the method is general and can swiftly be extended by including additional emoji intervals to the emojiPatterns array.
I realize reading your question again that you'd prefer substituting emojis with whitespace characters, rather than removing them (which the above filtering solution does). We can achieve this by replacing the .filter operation above with a conditional return .map operation instead, much like in your question
extension String {
var emojilessStringWithSubstitution: String {
let emojiPatterns = [UnicodeScalar(0x1F600)...UnicodeScalar(0x1F64F),
UnicodeScalar(0x1F300)...UnicodeScalar(0x1F5FF),
UnicodeScalar(0x1F680)...UnicodeScalar(0x1F6FF),
UnicodeScalar(0x2600)...UnicodeScalar(0x26FF),
UnicodeScalar(0x2700)...UnicodeScalar(0x27BF),
UnicodeScalar(0xFE00)...UnicodeScalar(0xFE0F)]
return self.unicodeScalars
.map { ucScalar in
emojiPatterns.contains{ $0 ~= ucScalar } ? UnicodeScalar(32) : ucScalar }
.reduce("") { $0 + String($1) }
}
}
I the above, the existing emoji intervals has been extended, as per your comment to this post (listing these intervals), such that the emoji check is now possibly exhaustive.
Swift 4:
extension String {
func stringByRemovingEmoji() -> String {
return String(self.filter { !$0.isEmoji() })
}
}
extension Character {
fileprivate func isEmoji() -> Bool {
return Character(UnicodeScalar(UInt32(0x1d000))!) <= self && self <= Character(UnicodeScalar(UInt32(0x1f77f))!)
|| Character(UnicodeScalar(UInt32(0x2100))!) <= self && self <= Character(UnicodeScalar(UInt32(0x26ff))!)
}
}
Emojis are classified as symbols by Unicode. Character sets are typically used in searching operations. So we will use Character sets a property that is symbols.
var emojiString = "Hey there 🖐, welcome"
emojiString = emojiString.components(separatedBy: CharacterSet.symbols).joined()
print(emojiString)
Output is
Hey there , welcome
Now observe the emoji is replaced by a white space so there is two white space and we replace it by the following way
emojiString.replacingOccurrences(of: " ", with: " ")
The above method replace parameter of: "two white space" to with: "single white space"
I found that the solutions given above did not work for certain characters such as 🏋️🏻♂️ and 🧰.
To find the emoji ranges, using regex I converted the full list of emoji characters to a file with just hex values. Then I converted them to decimal format and sorted them. Finally, I wrote a script to find the ranges.
Here is the final Swift extension for isEmoji().
extension Character {
func isEmoji() -> Bool {
let emojiRanges = [
(8205, 11093),
(12336, 12953),
(65039, 65039),
(126980, 129685)
]
let codePoint = self.unicodeScalars[self.unicodeScalars.startIndex].value
for emojiRange in emojiRanges {
if codePoint >= emojiRange.0 && codePoint <= emojiRange.1 {
return true
}
}
return false
}
}
For reference, here are the python scripts I wrote to parse the hex strings to integers and then find the ranges.
convert-hex-to-decimal.py
decimals = []
with open('hex.txt') as hexfile:
for line in hexfile:
num = int(line, 16)
if num < 256:
continue
decimals.append(num)
decimals = list(set(decimals))
decimals.sort()
with open('decimal.txt', 'w') as decimalfile:
for decimal in decimals:
decimalfile.write(str(decimal) + "\n")
make-ranges.py
first_line = True
range_start = 0
prev = 0
with open('decimal.txt') as hexfile:
for line in hexfile:
if first_line:
prev = int(line)
range_start = prev
first_line = False
continue
curr = int(line)
if prev + 1000 < curr: # 100 is abitrary to reduce number of ranges
print("(" + str(range_start) + ", " + str(prev) + ")")
range_start = curr
prev = curr
来源：https://stackoverflow.com/questions/36919125/swift-replacing-emojis-in-a-string-with-whitespace