ios 如何使用 Swift 将文本文件逐行加载到数组中？

How do I load a text file line by line into an array with Swift?

提问by Sebastian Krogull

How do I load a text file line by line into an arraywith swift?

如何将文本文件逐行加载到arraywith 中swift？

回答by Cezar

Something along the lines of:

类似的东西：

func arrayFromContentsOfFileWithName(fileName: String) -> [String]? {
    guard let path = NSBundle.mainBundle().pathForResource(fileName, ofType: "txt") else {
        return nil
    }

    do {
        let content = try String(contentsOfFile:path, encoding: NSUTF8StringEncoding)
        return content.componentsSeparatedByString("\n")
    } catch _ as NSError {
        return nil
    }
}

This approach assumes the file in question is located in your app bundle.

这种方法假设有问题的文件位于您的应用程序包中。

回答by dbn

Swift 3 version based on the accepted answer:

基于公认答案的 Swift 3 版本：

func arrayFromContentsOfFileWithName(fileName: String) -> [String]? {
    guard let path = Bundle.main.path(forResource: fileName, ofType: "txt") else {
        return nil
    }

    do {
        let content = try String(contentsOfFile:path, encoding: String.Encoding.utf8)
        return content.components(separatedBy: "\n")
    } catch {
        return nil
    }
}

回答by Imanou Petit

With Swift 5, according to your needs, you can choose one of the 3 following ways in order to solve your problem.

使用 Swift 5，您可以根据需要，选择以下 3 种方式之一来解决您的问题。

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#1. Using StringProtocol's components(separatedBy:)method

#1. usingStringProtocol的components(separatedBy:)方法

Foundationprovides Stringa method called components(separatedBy:)with the following declaration:

Foundation提供String了一个components(separatedBy:)使用以下声明调用的方法：

func components(separatedBy separator: CharacterSet) -> [String]

Returns an array containing substrings from the string that have been divided by characters in the given set.

返回一个数组，其中包含字符串中已被给定集合中的字符划分的子字符串。

The code sample below shows how to use components(separatedBy:)with its parameter set to CharacterSet.newlinesin order to load the content of a text file line by line into an array:

下面的代码示例显示了如何使用components(separatedBy:)其参数设置为CharacterSet.newlines将文本文件的内容逐行加载到数组中：

import Foundation

let path = Bundle.main.path(forResource: "Lorem Ipsum", ofType: "txt")!
let text = try! String(contentsOfFile: path, encoding: String.Encoding.utf8)
let lines = text.components(separatedBy: CharacterSet.newlines)

print(lines)

As an alternative, you can use the overloading of components(separatedBy:)that takes a parameter of type String. The code sample below shows how to use it:

作为替代方案，您可以使用带类型参数的的重载components(separatedBy:)String。下面的代码示例展示了如何使用它：

import Foundation

let path = Bundle.main.path(forResource: "Lorem Ipsum", ofType: "txt")!
let text = try! String(contentsOfFile: path, encoding: String.Encoding.utf8)
let lines = text.components(separatedBy: "\n")

print(lines)

?? You should however prefer the overloading of components(separatedBy:)that takes a CharacterSetparameter and use it with the value CharacterSet.newlinesas this will manage all new line characters (U+000A ~ U+000D, U+0085, U+2028, and U+2029).

?? 但是，您应该更喜欢重载components(separatedBy:)带CharacterSet参数并将其与值一起使用，CharacterSet.newlines因为这将管理所有换行符（U+000A ~ U+000D、U+0085、U+2028 和 U+2029）。

---

---

#2. Using StringProtocol's enumerateSubstrings(in:options:_:)method

#2. usingStringProtocol的enumerateSubstrings(in:options:_:)方法

Foundationprovides Stringa method called enumerateSubstrings(in:options:_:). The code sample below shows how to use enumerateSubstrings(in:options:_:)with optionsparameter value set to String.EnumerationOptions.byLinesin order to load the content of a text file line by line into an array:

Foundation提供String了一个名为enumerateSubstrings(in:options:_:). 下面示出了如何使用代码示例enumerateSubstrings(in:options:_:)用options的参数值集合来String.EnumerationOptions.byLines，以便通过线加载的文本文件行的内容到一个数组：

import Foundation

let path = Bundle.main.path(forResource: "Lorem Ipsum", ofType: "txt")!
let text = try! String(contentsOfFile: path, encoding: String.Encoding.utf8)

let range = text.startIndex ..< text.endIndex
var lines = [String]()
text.enumerateSubstrings(in: range, options: String.EnumerationOptions.byLines) {
    (substring, range, enclosingRange, stop) in
    guard let substring = substring else { return }
    lines.append(substring)
}

print(lines)

---

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#3. Using NLTokenizer's enumerateTokens(in:using:)method

#3. usingNLTokenizer的enumerateTokens(in:using:)方法

NLTokenizerhas a method called enumerateTokens(in:using:). enumerateTokens(in:using:)has the following declaration:

NLTokenizer有一个方法叫做enumerateTokens(in:using:). enumerateTokens(in:using:)有以下声明：

@nonobjc func enumerateTokens(in range: Range<String.Index>, using block: (Range<String.Index>, NLTokenizer.Attributes) -> Bool)

Enumerates over a given range of the string and calls the specified block for each token.

在给定的字符串范围内枚举并为每个标记调用指定的块。

The code sample below shows how to use enumerateTokens(in:using:)in order to load the content of a text file line by line into an array:

下面的代码示例显示了如何将enumerateTokens(in:using:)文本文件的内容逐行加载到数组中：

import Foundation
import NaturalLanguage

let path = Bundle.main.path(forResource: "Lorem Ipsum", ofType: "txt")!
let text = try! String(contentsOfFile: path, encoding: String.Encoding.utf8)

let tokenizer = NLTokenizer(unit: .paragraph)
tokenizer.setLanguage(.english)
tokenizer.string = text

var lines = [String]()
tokenizer.enumerateTokens(in: text.startIndex ..< text.endIndex) { (range, attributes) -> Bool in
    let line = String(text[range])
    lines.append(line)
    return true
}
print(lines)

回答by j.s.com

This works only until Xcode 6.1 beta 1. In 6.1 beta 2 you must write this:

这仅适用于 Xcode 6.1 beta 1。在 6.1 beta 2 中，您必须这样写：

var err: NSError? = NSError()
let s = String(contentsOfFile: fullPath, encoding: NSUTF8StringEncoding, error: &err)

Where fullPathis a string containing the full path to the file and NSUTF8StringEncodingis a predefined constant for UTF8-Encoding.

其中fullPath是包含文件完整路径的字符串，NSUTF8StringEncoding是 UTF8 编码的预定义常量。

You can also use NSMacOSRomanStringEncodingfor Mac files or NSISOLatin1StringEncodingfor Windows files.

您还可以NSMacOSRomanStringEncoding用于 Mac 文件或NSISOLatin1StringEncodingWindows 文件。

sis an optional String and you can look if reading the file was successful:

s是一个可选的字符串，您可以查看读取文件是否成功：

if (s != nil)
{
    return (s!) // Return the string as "normal" string, not as optional string
}

回答by hippo_san

If you are in Swift 2.0, you should use:

如果您使用的是 Swift 2.0，则应该使用：

let path = NSBundle.mainBundle().pathForResource(fileName, ofType: nil)
if path == nil {
  return nil
}

var fileContents: String? = nil
do {
  fileContents = try String(contentsOfFile: path!, encoding: NSUTF8StringEncoding)
} catch _ as NSError {
  return nil
}

回答by user3182143

My simple coding for you

我给你的简单编码

 let path = NSBundle.mainBundle().pathForResource("FileName", ofType: "txt")
 var text = String(contentsOfFile: path!, encoding: NSUTF8StringEncoding, error: nil)!
 println(text)
 var array = text.componentsSeparatedByString("\n")

回答by Abhishek Jain

Swift 3.0

斯威夫特 3.0

if let path = Bundle.main.path(forResource: <#FileName#>, ofType: "txt")
{
    do
    {
        let str = try String(contentsOfFile:path, encoding: String.Encoding.utf8)
        return str.components(separatedBy: "\n")
    }
    catch
    {

    }
}
else
{
    return nil
}

回答by Alessandro Mattiuzzi

For me works as follow:

对我来说工作如下：

let myFileURL = NSBundle.mainBundle().URLForResource("listacomuni", withExtension: "txt")!
let myText = try! String(contentsOfURL: myFileURL, encoding: NSISOLatin1StringEncoding)
print(String(myText))

回答by Chris Gunawardena

If you want to read a csv file of numeric data. (based on Cezar's answer)

如果要读取数字数据的 csv 文件。（基于 Cezar 的回答）

func get_csv_data() -> [[Double]] {
    guard let path = NSBundle.mainBundle().pathForResource("filename_without_extension", ofType: "csv") else {
        return []
    }
    do {
        let content = try String(contentsOfFile:path, encoding: NSUTF8StringEncoding)
        let line_str_array = content.componentsSeparatedByString("\n")
        return line_str_array.map {
            let field_str_array = ##代码##.componentsSeparatedByString(",")
            return field_str_array.map {
                Double(##代码##)!
            }
        }
    } catch _ as NSError {
        return []
    }
}