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c#listcustom-lists
Christopher Littlewood
Christopher Littlewood

Reputation: 803

Updating Data in List

I am trying to update the items in a list with user provided parameters. I am using a custom list type AbilityScores. See below:

class AbilityScores
{
    public string Strength { get; set; }
    public string Dexterity { get; set; }
    public string Constitution { get; set; }
    public string Intelligence { get; set; }
    public string Wisdom { get; set; }
    public string Charisma { get; set; }
}

I am trying to add the update a specific part of the list:

if(ability == "Strength"){
            abilityScores.Where(w => w.Strength == "Strength").ToList().ForEach(s => s.Strength = scoreIncrease.ToString());
}

Both ability and scoreIncrease are user provided parameters. Here I am updating the strength attribute. I understand most of what I read here:

c# Update item in list

But I do not understand what w => w.Strength == "Strength" is actually doing. How would I use this in my code? I am really new to C# and lists. Any help would be greatly appreciated.

Upvotes: 0

Views: 403

Answers (4)

Michał Turczyn
Michał Turczyn

Reputation: 37367

You could try iterating over subset of your list specified by Where:

foreach(var s in abilityScores.Where(w => w.Strength == ability))
    s.Strength = scoreIncrease.ToString();

Upvotes: 0

ChristianMurschall
ChristianMurschall

Reputation: 1671

You are using a linq statement. It does the same as the following traditional way:

if (ability == "Strength")
{
    foreach (var abilityScore in abilityScores)
    {
        if (abilityScore.Strength == "Strength")
        {
            abilityScore.Strength = scoreIncrease.ToString();
        }
    }
}

Upvotes: 0

Sidmarconius
Sidmarconius

Reputation: 15

w => w.Strength == "Strength"compares on every item in the list, whatever is property Strength equal to string "Strength". Where function uses lambda expression for criteria which part of list you want to select.

More about lambda expression: https://weblogs.asp.net/dixin/understanding-csharp-features-5-lambda-expression

Upvotes: 0

Antoine V
Antoine V

Reputation: 7204

You don't need the Where at all. It is used when you want to filter somes item by a condition defined by a Predicate

In your case, you want to update the value Strength for all objects.

Using a ForEach is enough

foreach(var s in abilityScores)
{
    s.Strength = scoreIncrease.ToString()
}

Upvotes: 2

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