How do I split a word's letters into an Array in C#?

问题

How do I split a string into an array of characters in C#?

Example String word used is "robot".

The program should print out:

r
o
b
o
t

The orginal code snippet:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.IO;
using System.Text.RegularExpressions;


namespace Testing
{
class Program
{
    static void Main(string[] args)
    {
        String word = "robot";

        String[] token = word.Split(); // Something should be placed into the () to 
        //print letter by letter??

        foreach (String r in token)
        {
            Console.WriteLine(r);
        }
    }
}
}

How can the codes be correctly implemented?

回答1:

Why not this?

public void WriteLetters(string s)
{
    foreach (char c in s)
    {
        Console.WriteLine(c); 
    }
}

If you really want to see it in an explicit character array, do the following:

string s = "robot";
char[] charArray = s.ToCharArray();

If you then want to print that out (1 per line), do the following:

for (int i = 0; i < charArray.Length; i++)
{
    Console.WriteLine(charArray[i]);
}

I'm not really sure what you're trying to do, so I may be way off base.

If by tokenize, you mean store the characters in an array, you already have that in a String object¹.

_{¹ Not actually true, because String uses an indexer to iterate through the character values, whereas in C/C++, a string is actually an array of characters. For our purposes, we can treat a string as if it is an array of characters}

回答2:

The class String implements IEnumerable<char> and therefore to run through the letters of a string, you can just grab an IEnumerator<char> and process the chars one at a time. One way to do this is using a foreach:

foreach(char c in "robot") {
    Console.WriteLine(c);
}

If you need each char in an array you can just use String.ToCharArray:

char[] letters = "robot".ToCharArray();

回答3:

Do you mean something like this?

foreach(var alpha in myString.Where(c => Char.IsLetter(c)))
{
    Console.WriteLine(alpha);
}

回答4:

You can using ToArray() method to return the char array.

string word = "robot";
char[] array = word.ToArray();

回答5:

You are trying to do too much.

Try this:

        String word = "robot";

        foreach (char letter in word)
        {
            Console.WriteLine(letter);
        }

Edit:

To split the string into character array, without a loop, you can do this: word.ToCharArray()

回答6:

Seems everyone wants to convert a String into an Array of Chars.

How about

for(int i = 0; i < tmpString.Length; i++)
Console.WriteLine(tmpString[i]);

Now you have the speed of a char array without the extra memory of making a copy.

edit: A String is an array of chars internally, there just isn't a way to change their values because String are immutable. But you can read from that char array. String = Read-Only char array.

I can't think of any reason to convert a String into a Char[] unless you wanted to "edit" the string.

long lTicks;
            char[] tmpChar = { 'a', 'b', 'c', 'd', 'e' };
            String tmpString = "abcde";
            char chRead;

            lTicks = DateTime.Now.Ticks;
            for (int i = 0; i < 100000000; i++)
                chRead = tmpChar[i%5];

            Console.WriteLine(((DateTime.Now.Ticks - lTicks) / 10000).ToString());

            lTicks = DateTime.Now.Ticks;
            for (int i = 0; i < 100000000; i++)
                chRead = tmpChar[i % 5];

            Console.WriteLine(((DateTime.Now.Ticks - lTicks) / 10000).ToString());

            lTicks = DateTime.Now.Ticks;
            for (int i = 0; i < 100000000; i++)
                chRead = tmpString[i%5];

            Console.WriteLine(((DateTime.Now.Ticks - lTicks) / 10000).ToString());

            lTicks = DateTime.Now.Ticks;
            for (int i = 0; i < 100000000; i++)
                chRead = tmpString[i % 5];

            Console.WriteLine(((DateTime.Now.Ticks - lTicks) / 10000).ToString());

            Console.ReadLine();

Kind of funny, the String is actually consistently faster than the Char[]. I ran each twice to make sure there wasn't a load time issue affecting the results. Compiled as Release with optimizations. Char[] was ~1950ms and String ~1850ms every run for me.

来源：https://stackoverflow.com/questions/4246856/how-do-i-split-a-words-letters-into-an-array-in-c

标签

.net

string

tokenize