我需要从字符串中提取数字并将它们放入 Swift 中的新数组中。
var str = "I have to buy 3 apples, 7 bananas, 10eggs"
我尝试循环每个字符,但我不知道比较字符和 Int。
迅捷 3/4
let string = "0kaksd020dk2kfj2123"
if let number = Int(string.components(separatedBy: CharacterSet.decimalDigits.inverted).joined()) {
// Do something with this number
}
您还可以进行扩展,例如:
extension Int {
static func parse(from string: String) -> Int? {
Int(string.components(separatedBy: CharacterSet.decimalDigits.inverted).joined())
}
}
然后像这样使用它:
if let number = Int.parse(from: "0kaksd020dk2kfj2123") {
// Do something with this number
}
首先,我们分割字符串,以便我们可以处理单个项目。然后我们使用
NSCharacterSet
仅选择数字。
import Foundation
let str = "I have to buy 3 apples, 7 bananas, 10eggs"
let strArr = str.split(separator: " ")
for item in strArr {
let part = item.components(separatedBy: CharacterSet.decimalDigits.inverted).joined()
if let intVal = Int(part) {
print("this is a number -> \(intVal)")
}
}
斯威夫特4:
let string = "I have to buy 3 apples, 7 bananas, 10eggs"
let stringArray = string.components(separatedBy: CharacterSet.decimalDigits.inverted)
for item in stringArray {
if let number = Int(item) {
print("number: \(number)")
}
}
使用 Swift 提取正则表达式匹配中的“正则表达式辅助函数”:
func matchesForRegexInText(regex: String!, text: String!) -> [String] {
let regex = NSRegularExpression(pattern: regex,
options: nil, error: nil)!
let nsString = text as NSString
let results = regex.matchesInString(text,
options: nil, range: NSMakeRange(0, nsString.length))
as! [NSTextCheckingResult]
return map(results) { nsString.substringWithRange($0.range)}
}
您可以轻松实现这一目标
let str = "I have to buy 3 apples, 7 bananas, 10eggs"
let numbersAsStrings = matchesForRegexInText("\\d+", str) // [String]
let numbersAsInts = numbersAsStrings.map { $0.toInt()! } // [Int]
println(numbersAsInts) // [3, 7, 10]
模式
"\d+"
匹配一个或多个十进制数字。
当然,不使用辅助函数也可以完成同样的操作 如果您出于某种原因喜欢这样:
let str = "I have to buy 3 apples, 7 bananas, 10eggs"
let regex = NSRegularExpression(pattern: "\\d+", options: nil, error: nil)!
let nsString = str as NSString
let results = regex.matchesInString(str, options: nil, range: NSMakeRange(0, nsString.length))
as! [NSTextCheckingResult]
let numbers = map(results) { nsString.substringWithRange($0.range).toInt()! }
println(numbers) // [3, 7, 10]
没有正则表达式的替代解决方案:
let str = "I have to buy 3 apples, 7 bananas, 10eggs"
let digits = "0123456789"
let numbers = split(str, allowEmptySlices: false) { !contains(digits, $0) }
.map { $0.toInt()! }
println(numbers) // [3, 7, 10]
let str = "Hello 1, World 62"
let intString = str.componentsSeparatedByCharactersInSet(
NSCharacterSet
.decimalDigitCharacterSet()
.invertedSet)
.joinWithSeparator("")
这将为您提供一个包含所有数字的字符串,然后您可以这样做:
let int = Int(intString)
请确保将其打开,因为
let int = Int(intString)
是可选的。
对我来说,将其作为字符串扩展更有意义,可能这是一个品味问题:
extension String {
func parseToInt() -> Int? {
return Int(self.components(separatedBy: CharacterSet.decimalDigits.inverted).joined())
}
}
所以可以这样使用:
if let number = "0kaksd020dk2kfj2123".parseToInt() {
// Do something with this number
}
改编自@flashadvanced's answer, 我发现以下内容对我来说更短更简单。
let str = "I have to buy 3 apples, 7 bananas, 10eggs"
let component = str.componentsSeparatedByCharactersInSet(NSCharacterSet.decimalDigitCharacterSet().invertedSet)
let list = component.filter({ $0 != "" }) // filter out all the empty strings in the component
print(list)
在游乐场尝试过,有效
希望有帮助:)
斯威夫特2.2
let strArr = str.characters.split{$0 == " "}.map(String.init)
for item in strArr {
let components = item.componentsSeparatedByCharactersInSet(NSCharacterSet.decimalDigitCharacterSet().invertedSet)
let part = components.joinWithSeparator("")
if let intVal = Int(part) {
print("this is a number -> \(intVal)")
}
}
// This will only work with single digit numbers. Works with “10eggs” (no space between number and word
var str = "I have to buy 3 apples, 7 bananas, 10eggs"
var ints: [Int] = []
for char:Character in str {
if let int = "\(char)".toInt(){
ints.append(int)
}
}
这里的技巧是你可以检查字符串是否是整数(但不能检查字符是否是整数)。
通过循环遍历字符串的每个字符,使用字符串插值从该字符创建一个字符串,并检查该字符串是否被转换为整数。
如果可以的话,将其添加到数组中。
// This will work with multi digit numbers. Does NOT work with “10 eggs” (has to have a space between number and word)
var str = "I have to buy 3 apples, 7 bananas, 10 eggs"
var ints: [Int] = []
var strArray = split(str) {$0 == " "}
for subString in strArray{
if let int = subString.toInt(){
ints.append(int)
}
}
在这里,我们在任意空格处分割字符串,并为长字符串中的每个子字符串创建一个数组。
我们再次检查每个字符串,看看它是否是(或可以转换为)整数。
斯威夫特5:
extension String {
var allNumbers: [Int] {
let numbersInString = self.components(separatedBy: .decimalDigits.inverted).filter { !$0.isEmpty }
return numbersInString.compactMap { Int($0) }
}
}
您可以获得所有数字,例如
var str = "I have to buy 3 apples, 7 bananas, 10eggs"
// numbers = [3, 7, 10]
numbers = str.allNumbers
感谢所有回答我问题的人。
我正在寻找一个仅使用 swift 语法的代码块,因为我现在只学习语法..
我的问题得到了答案。也许这不是一个更容易解决的方法,但它只使用了 swift 语言。
var article = "I have to buy 3 apples, 7 bananas, 10 eggs"
var charArray = Array(article)
var unitValue = 0
var total = 0
for char in charArray.reverse() {
if let number = "\(char)".toInt() {
if unitValue==0 {
unitValue = 1
}
else {
unitValue *= 10
}
total += number*unitValue
}
else {
unitValue = 0
}
}
println("I bought \(total) apples.")