删除Swift中String对象中特定字符后所有字符的更优雅方法是什么

What is the more elegant way to remove all characters after specific character in the String object in Swift?

删除Swift中String对象中特定字符后所有字符的更优雅方法是什么？

Suppose that I have the following string:

假设我有以下字符串：

str.str

str.str

and I need to remove the ".str" from it. How can I do it?

我需要从中删除“.str”。我该怎么做？

Thanks in advance.

提前致谢。

3 个解决方案

#1

Here is a way to do it:

这是一种方法：

var str = "str.str"

if let dotRange = str.rangeOfString(".") {
    str.removeRange(dotRange.startIndex..<str.endIndex)
}

Update In Swift 3 it is:

在Swift 3中更新它是：

var str = "str.str"

if let dotRange = str.range(of: ".") {
  str.removeSubrange(dotRange.lowerBound..<str.endIndex)
}

#2

Quite a compact way would be:

相当紧凑的方式是：

var str = "str.str"
str = str.componentsSeparatedByString(".")[0]

Another option you might be interested in, which works for your example 'str.str' but doesn't fit your specification is:

您可能感兴趣的另一个选项，适用于您的示例'str.str'，但不符合您的规范：

str = str.stringByDeletingPathExtension
// Returns a new string made by deleting the extension (if any, and only the last)
// from the `String`

#3

I think this is better approach:

我认为这是更好的方法：

Update with Swift 4: (substring is now deprecated)

使用Swift 4更新:(现在不推荐使用子字符串）

let smth = "element=value"

if let index = (smth.range(of: "=")?.upperBound)
{
  //prints "value"
  let afterEqualsTo = String(smth.suffix(from: index))

  //prints "element="
  let beforeEqualsToContainingSymbol = String(smth.prefix(upTo: index))
}

if let index = (smth.range(of: "=")?.lowerBound)
{
  //prints "=value"
  let afterEqualsToContainingSymbol = String(smth.suffix(from: index))

  //prints "element"
  let beforeEqualsTo = String(smth.prefix(upTo: index))
}

#1