使用Swift查找字符串中的第一个非重复字符
使用Swift查找字符串中的第一个非重复字符
提问于 2014-12-07 08:08:12
这将查找数组中的重复项，但我要查找的是能够找到字符串中第一个非重复字符的内容。我一直在试着找出一种方法来做这件事，但我想不出来。这是我最接近的一次了。
var strArray = ["P","Q","R","S","T","P","R","A","T","B","C","P","P","P","P","P","C","P","P","J"]
println(strArray)
var filter = Dictionary<String,Int>()
var len = strArray.count
for var index = 0; index < len ;++index {
var value = strArray[index]
if (filter[value] != nil) {
strArray.removeAtIndex(index--)
len--
}else{
filter[value] = 1
}
}
println(strArray)回答 7
Stack Overflow用户
回答已采纳
发布于 2014-12-07 08:37:56
为了判断字符是否重复，遍历整个数组一次，递增字典中出现的次数：
let characters = ["P","Q","R","S","T","P","R","A","T","B","C","P","P","P","P","P","C","P","P","J"]
var counts: [String: Int] = [:]
for character in characters {
counts[character] = (counts[character] ?? 0) + 1
}
let nonRepeatingCharacters = characters.filter({counts[$0] == 1})
// ["Q", "S", "A", "B", "J"]
let firstNonRepeatingCharacter = nonRepeatingCharacters.first!
// "Q"Stack Overflow用户
发布于 2020-02-07 19:53:01
这是一个简单的解决方案
let inputString = "PQRSTPRATBCPPPPPCPPJ"
func nonRepeat (_ input: String) -> String {
for char in input {
if input.firstIndex(of: char) == input.lastIndex(of: char) {
return String(char)
}
}
return ""
}
print (nonRepeat(inputString))在上面的示例中，它将打印"Q“
Stack Overflow用户
发布于 2018-06-02 04:45:15
func firstNonRepeatedCharacter(input: String) -> Character?{
var characterCount : [Character : Int] = [:]
var uniqueCharacter: Character?
for character in input{
if let count = characterCount[character]{
characterCount[character] = count + 1
if(uniqueCharacter == character)
{
uniqueCharacter = nil
}
}
else{
characterCount[character] = 1
if(uniqueCharacter == nil){
uniqueCharacter = character
}
}
}
return uniqueCharacter
}无需额外的循环即可从characterCount字典中查找字符
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/27338045
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