如何将字符串与数组项的特定部分进行比较？

Question

I have an array arr[] of string type with array-items as follows:

arr[0]= "2/13/2019|202"
arr[1]= "2/14/2019|197"
arr[2]= "2/15/2019|101"
arr[4]= "2/16/2019|271"
arr[5]= "2/17/2019|199"

I want to get an array-item that matches my string "2/15/2019" so I can get "2/15/2019|101". in short, I just want to compare my string with the array-item string till "|" and rest strong will not be considered for comparison. how can I get it?

Answer 1

You can use Linq to get the data you are looking for.

• use Contains(string) to check if there is one or more elements that match your criteria
• if it does, get the first one from the list (or you can assign that list to a variable and iterate through each of it)
• Split the value and get the value after |
• Use ?. after FirstOrDefault() method to ensure you dont get NullReferenceException when you run Split() .
• Use validation to ensure result is not null.

var result = arr.FirstOrDefault(x => x.Contains("2/15/2019"))?.Split('|')[1];
// result contains 101

Enumerable.FirstOrDefault : Returns the first element of a sequence, or a default value if no element is found

Answer 2

You could use Where and StartWith

var results = arr.Where(x => x.StartsWith("2/15/2019")); 

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Additional Resources

Enumerable.Where Method

Filters a sequence of values based on a predicate.

String.StartsWith Method

Determines whether the beginning of this string instance matches a specified string.

Answer 3

Use where and contains

           string getdata = "2/15/2019";
            string[] arr = new string[5];
            arr[0] = "2/13/2019|202";
            arr[1] = "2/14/2019|197";
            arr[2] = "2/15/2019|101";
            arr[3] = "2/16/2019|271";
            arr[4] = "2/17/2019|199";

            var op = arr.Where(a => a.Contains(getdata)).FirstOrDefault();