C#怎么计算一列数组的平均值，这是我程序，求大神帮忙看一下，哪里有问题。

[louguanghai]

我的数组中的数据是从dataGridView1控件中来的，数组就1列，数组中的数据都是3.35，3.54，3.56.....这样的。然后想把这个数据求一下平均值，然后显示到textBox2控件上去。

string[] sample = new string[dataGridView1.Rows.Count];
for (int i = 0; i < dataGridView1.Rows.Count; i++)
{
sample[i] = dataGridView1.Rows[i].Cells[0].ToString();
}

//计算平均值
float sum = 0f, max = 0f, min = 0f;
int num = 100;

for (int i = 0; i < num;i ++)
{
sum += sample[i]; //这句话显示有问题
}
textBox2.Text = (sum / num).ToString();

[bdmh]

sum += Convert.ToSingle(sample[i]);

[louguanghai]

引用 1 楼 bdmh 的回复:

sum += Convert.ToSingle(sample[i]);

我把程序改成这样了：
string[] sample = new string[dataGridView1.Rows.Count];
for (int i = 0; i < dataGridView1.Rows.Count; i++)
{
sample[i] = dataGridView1.Rows[i].Cells[0].ToString();
}

//计算平均值
float sum = 0;
int num = 100;

for (int i = 0; i < num;i ++)
{
sum += Convert.ToSingle(sample[i]);
}
textBox2.Text = (sum / num).ToString();
但是在调试的时候出现一下问题：

[娃都会打酱油了]

sample.Sum()/sample.Length

[louguanghai]

引用 4 楼 starfd 的回复:

sample.Sum()/sample.Length

我不太看得懂你的意思，能帮我写下完整代码吗，谢谢！

[娃都会打酱油了]

 double[] sample = new string[dataGridView1.Rows.Count];
            for (int i = 0; i < dataGridView1.Rows.Count; i++)
            {
                sample[i] = double.Parse(dataGridView1.Rows[i].Cells[0].Value);
            }

var avg = sample.Sum()/sample.Length;
var min = sample.Min();
var max = sample.Max();

[娃都会打酱油了]

var avg = sample.Average();

上面多此一举了

[louguanghai]

引用 6 楼 starfd 的回复:

 double[] sample = new string[dataGridView1.Rows.Count];
            for (int i = 0; i < dataGridView1.Rows.Count; i++)
            {
                sample[i] = double.Parse(dataGridView1.Rows[i].Cells[0].Value);
            }

var avg = sample.Sum()/sample.Length;
var min = sample.Min();
var max = sample.Max();

大神我调用了你的程序,发现没法用：

[娃都会打酱油了]

double[] sample = new double[dataGridView1.Rows.Count];
            for (int i = 0; i < dataGridView1.Rows.Count; i++)
            {
                sample[i] = double.Parse(dataGridView1.Rows[i].Cells[0].Value);
            }
 
var avg = sample.Sum()/sample.Length;
var min = sample.Min();
var max = sample.Max();

抄你的代码部分没改……

[louguanghai]

引用 9 楼 starfd 的回复:

double[] sample = new double[dataGridView1.Rows.Count];
            for (int i = 0; i < dataGridView1.Rows.Count; i++)
            {
                sample[i] = double.Parse(dataGridView1.Rows[i].Cells[0].Value);
            }
 
var avg = sample.Sum()/sample.Length;
var min = sample.Min();
var max = sample.Max();

抄你的代码部分没改……

还有一句话无法调试呢~~~：

[娃都会打酱油了]

double[] sample = new double[dataGridView1.Rows.Count];
            for (int i = 0; i < dataGridView1.Rows.Count; i++)
            {
                sample[i] = double.Parse(dataGridView1.Rows[i].Cells[0].Value.ToString());
            }
  
var avg = sample.Average();
var min = sample.Min();
var max = sample.Max();

[louguanghai]

引用 11 楼 starfd 的回复:

double[] sample = new double[dataGridView1.Rows.Count];
            for (int i = 0; i < dataGridView1.Rows.Count; i++)
            {
                sample[i] = double.Parse(dataGridView1.Rows[i].Cells[0].Value.ToString());
            }
  
var avg = sample.Average();
var min = sample.Min();
var max = sample.Max();

非常感谢！！！ 我还有一个问题： 我想把平均值avg的值显示到textBox2控件上去，最大值max的值显示到textBox3控件上去，最小值min的值显示到textBox4控件上去，怎么写代码？

[娃都会打酱油了]

this.TextBox2.Text=avg;
this.TextBox3.Text=max;
this.TextBox4.Text=min;

接上面的代码……虽说初学，但这个还是要懂的啊

[渃水]

引用 14 楼 wyd1520 的回复:

sample.Select(o => double.Parse(o)).Average(); 一句搞定

正解，有直接求平均值的方法啊

[本拉灯]

sample.Select(o => double.Parse(o)).Average(); 一句搞定

[qq_33435631]

public static void avg日报(string tagname) { DateTime start1=Convert.ToDateTime(GrpManager.日报表.日历5.Text +" "+"00:00:00");//控件 DateTime end1=Convert.ToDateTime(GrpManager.日报表.日历5.Text +" "+"01:00:00"); string sql1=string.Format("select max(TagValue) from "+tagname+" where TagChangeTime >'{0}' and TagChangeTime <'{1}'",start1,end1); AVG.avg1=Defined.avg(sql1); } 我这里是工程上用的一条c# 出来的数就是平均值 我现在想要一个最大值 应该怎么改？

[lshfong]

数组相加后，除以数组长度

[suiyuezhang]

double[] sample = new double[dataGridView1.Rows.Count];
for (int i = 0; i < dataGridView1.Rows.Count; i++)
{
sample[i] = double.Parse(dataGridView1.Rows[i].Cells[0].Value.ToString()); //这里显示未将对象引用设置到对象的实例，请问该怎么修改
}

var avg = sample.Average();

this.textBox2.Text = avg.ToString();