How to read multiple CSV file in a folder in

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Age i want to calculate the median of that column along with other values which are higher or lower than the average value

What I have tried:

.

Posted 24-Mar-18 23:21pm

Akhil Jain

Updated 25-Mar-18 6:09am

v4

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RickZeeland · Answer 1 · 2018-03-24T23:31:00

Here is an interesting library for reading and writing CSV files: GitHub - JoshClose/CsvHelper: Library to help reading and writing CSV files[^]

You can also use LINQ, here is an example to calculate the average age:

// Read CSV using LINQ
static void ReadFileLinq(string fileName)
{
    IEnumerable<string> strCSV = File.ReadLines(fileName, Encoding.ASCII).Skip(1);

    var results = from str in strCSV
                  let tmp = str.Split(',')
                  .Select(x => x.Replace("?", string.Empty))
                  select new { Age = DateTime.Parse(tmp.ElementAt(0))};

    // caching for performance
    var query = results.OrderBy(x => x.Age));

    foreach (var item in query)
    {
        Console.WriteLine(item.Age);
    }

    Console.WriteLine(string.Empty);
    Console.WriteLine("Average age = " + query.Average(x => x.Age));
    Console.WriteLine(string.Empty);
}

As LINQ does not have a Median function, you will have to write this function yourself.
Here is an example on CodeProject: Using LINQ to Calculate Basic Statistics[^]

OriginalGriff · Answer 2 · 2018-03-24T23:33:00

Solution 2

Start by working out how you are going to read the CSV data: there are a whole load of ways including writing your own CSV processor, but A Fast CSV Reader[^] is a good way to start.
When you have the data, processing the column to get the average, median, or mean is trivial!

Posted 24-Mar-18 23:33pm

OriginalGriff

Comments

Maciej Los 25-Mar-18 10:28am

5ed!

Maciej Los · Answer 3 · 2018-03-25T03:37:00

It's easy to calculate median[^], because it's a middle/central value* of ordered list.
* - for even number of values - it's an average of two values from middle of ordered list
Follow the above link for further details.

C#

//case #1 - even number of values
//int[] ages = {100,22,13,43,25,61,17,80}; 
//result: AVG(25,43) = 34

//case #2 - odd number of values
int[] ages = {100,22,13,43,25,61,17,80,29}; 
//result: 29

//does the number of values is even?
bool isEvenNumberOfValues = ages.Length % 2 == 0;
int toSkip = isEvenNumberOfValues ? (ages.Length/2)-1 : ages.Length/2;
int toTake = isEvenNumberOfValues ? 2 : 1;
//get middle value from ordered list 
var result = ages.OrderBy(x=>x).Skip(toSkip).Take(toTake).Average();
Console.WriteLine("Median for: [{0}] is {1}", string.Join(",", ages.OrderBy(x=>x)), result);

All you need to do is to create Median function (based on above code). A Median function have to:
1. take an array of numbers as an input argument
2. return double

Another implementation of Median function, you'll find here: How to: Add Custom Methods for LINQ Queries (C#) | Microsoft Docs[^]

Patrice T · Answer 4 · 2018-03-24T23:51:00

Solution 3

Quote:
I want to read Csv files that is there in sample(name) folder

2 steps:
- get the list of csv files in directory
- read them 1 by 1

You may need to learn programming.

Posted 24-Mar-18 23:51pm

Patrice T

Updated 25-Mar-18 1:00am

v3

Comments

Maciej Los 25-Mar-18 10:32am

Although your answer is incomplete, i voted 5 to counteract down-vote.

Patrice T 25-Mar-18 10:39am

Thank you.
The question is not very complete either.

How to read multiple CSV file in a folder in

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