Go through a string and check if contains a char and save the chars before in a list

Question

I want go through a string, and check if in the string is a char available. For example: My string is: string test = "100+20+3-17+2" So now I go through my string and check the chars:

List<string> numbers= new List<string>();
foreach( char c in test)
{
   if (c =='+'|| c =='-'||c =='/'||c =='*')
   {
     //Now here i want to save all chars before '+' '-'  '/'  '*' in my list numbers. in this example: save 100, 20,3,17,2 in my list
   }
}

How would you do this?

_"here i want to save all chars"_ what means _save_? Is it important to save the pairs which belong to specific characters like in `100+20` or doesn't it matter if you don't know later to which character they belonged, like in `100+20/30`? — Tim Schmelter, Jun 17 '15 at 07:34
@Tim Schmelter No i want know later which character will be entered. But i want further than total the whole numbers.. I think that will be very difficult — saaami11, Jun 17 '15 at 08:10

score 2 · Accepted Answer · answered Jun 17 '15 at 07:33

2

just split your string with the characters

List<string> numbers = new List<string>();
string test = "100+20+3-17+2";
char[] chars = new char[] { '+', '-', '*', '/' };
numbers = test.Split(chars).ToList();

answered Jun 17 '15 at 07:33

fubo

44,811
17
103
137

Hello fubo, nice that solution works fine. But now if i want total the numbers, how can i work furhter with the numbers? – saaami11 Jun 17 '15 at 07:40
@saaami11 are you expecting 108? – Sarvesh Mishra Jun 17 '15 at 07:50
Yes Sarvesh im expecting 108 – saaami11 Jun 17 '15 at 07:54
@saaami11 thats a completely different question. you need to remember the arithmetic operators. and what about multiplication and division first, then addition and subtraction? – fubo Jun 17 '15 at 09:06
Hmm yeah thats my problem., it want be so easy to make that hm? – saaami11 Jun 17 '15 at 09:08
no not so easy http://stackoverflow.com/questions/333737/c-sharp-evaluating-string-342-yield-int-18 – fubo Jun 17 '15 at 09:12

Gentian Kasa · Answer 2 · 2015-06-17T07:41:30.990

I'd go with a StringBuilder. As you go through the original string to check chars add them to the StringBuilder. When you find a splitter char add StringBuilder.ToString in the list and empty the StringBuilder.

The code should look something like the following (haven't tested it):

List<string> numbers= new List<string>();
StringBuilder sb = new StringBuilder();

foreach( char c in test)
{
    if (c =='+'|| c =='-'||c =='/'||c =='*')
    {
        //Now here i want to save all chars before '+' '-'  '/'  '*' in my list numbers. in this example: save 100, 20,3,17,2 in my list

        numbers.Add(sb.ToString());
        sb.Clear();
    }
    else
    {
        sb.Append(c);
    }
}

score 1 · Answer 3 · answered Jun 17 '15 at 07:38

1

If char not in '+', '-', '/', '*', you can concat the chars in string. When operator comes you can add the sting to list, and empty string

List<string> numbers= new List<string>();
string curNumber="";
foreach( char c in test)
{
   if (c =='+'|| c =='-'||c =='/'||c =='*')
   {
     numbers.Add(curNumber);
     curNumber="";
   }
   else
   {
     //also you can add operators in other list here
     curNumber+=c.ToString();
   }
}
numbers.Add(curNumber);

answered Jun 17 '15 at 07:38

cevatsenturk

31
4

Like i ask above, but now if i want total the numbers, how can i work furhter with the numbers? The result in this example is 108? – saaami11 Jun 17 '15 at 07:59

Uriel Zilberberg · Answer 4 · 2015-06-17T07:34:19.883

0

use String.Split(Char[]) to get an array of the splitted string

edited Jun 17 '15 at 07:34

answered Jun 17 '15 at 07:32

Uriel Zilberberg

104
2

"this" isn't very descriptive, you should include the relevant information from that link in your answer. If the link were to die, then so would your answer – Sayse Jun 17 '15 at 07:33

Go through a string and check if contains a char and save the chars before in a list

4 Answers4