Input the following formula in `C1`:

`=IF(ISNA(A1),B1,A1*B1`)

***Screenshots:***

**When #N/A:**

![enter image description here][1]

**When not #N/A:**

![enter image description here][2]

Let us know if this helps.


  [1]: http://i.stack.imgur.com/wtYcn.png
  [2]: http://i.stack.imgur.com/6vBiI.png

&quot;N/A&quot; is not a string it is an error, try this:

    =if(ISNA(A1),C1)

you have to place this fomula in cell B1 so it will get the value of your formula

A possible alternative approach in Excel 2010 or later versions:

`AGGREGATE(6,6,A1,B1)`

In `AGGREGATE` function the first `6` indicates `PRODUCT` operation and the second `6` denotes &quot;ignore errors&quot;

[untested]

use this formula to return the results for case of &quot;FALSE&quot;/&quot;TRUE&quot;:

=IF(ISNA(A1)=TRUE, B1, A1*B1) 

I tested the speed of `memcpy()` noticing the speed drops dramatically at i*4KB. The result is as follow: the Y-axis is the speed(MB/second) and the X-axis is the size of buffer for `memcpy()`, increasing from 1KB to 2MB. Subfigure 2 and Subfigure 3 detail the part of 1KB-150KB and 1KB-32KB.

Environment：

CPU : Intel(R) Xeon(R) CPU E5620  @ 2.40GHz 

OS :  2.6.35-22-generic #33-Ubuntu

GCC compiler flags : -O3 -msse4 -DINTEL_SSE4 -Wall -std=c99
 
![Graphs of memcpy speed showing troughs every 4k][1]

I guess it must be related to caches, but I can&#39;t find a reason from the following cache-unfriendly cases:

 * https://stackoverflow.com/questions/12264970/why-is-my-program-slow-when-looping-over-exactly-8192-elements

 * https://stackoverflow.com/questions/11413855/why-is-transposing-a-matrix-of-512x512-much-slower-than-transposing-a-matrix-of

Since the performance degradation of these two cases are caused by unfriendly loops which read scattered bytes into the cache, wasting the rest of the space of a cache line.

Here is my code:

    void memcpy_speed(unsigned long buf_size, unsigned long iters){
        struct timeval start,  end;
        unsigned char * pbuff_1;
        unsigned char * pbuff_2;

        pbuff_1 = malloc(buf_size);
        pbuff_2 = malloc(buf_size);

        gettimeofday(&amp;start, NULL);
        for(int i = 0; i &lt; iters; ++i){
            memcpy(pbuff_2, pbuff_1, buf_size);
        }   
        gettimeofday(&amp;end, NULL);
        printf(&quot;%5.3f\n&quot;, ((buf_size*iters)/(1.024*1.024))/((end.tv_sec - \
        start.tv_sec)*1000*1000+(end.tv_usec - start.tv_usec)));
        free(pbuff_1);
        free(pbuff_2);
    }

UPDATE
=====
Considering suggestions from @usr, @ChrisW and @Leeor, I redid the test more precisely and the graph below shows the results. The buffer size is from 26KB to 38KB, and I tested it every other 64B(26KB, 26KB+64B, 26KB+128B, ......, 38KB). Each test loops 100,000 times in about 0.15 second. The interesting thing is the drop not only occurs exactly in 4KB boundary, but also comes out in 4*i+2 KB, with a much less falling amplitude.


![More graphs showing performance drops][2]


PS
==
@Leeor offered a way to fill the drop, adding a 2KB dummy buffer between `pbuff_1` and `pbuff_2`. It works, but I am not sure about Leeor&#39;s explanation.


![enter image description here][3] 


  [1]: http://i.stack.imgur.com/TJ4Xx.png
  [2]: http://i.stack.imgur.com/qto0R.png
  [3]: http://i.stack.imgur.com/NL3uy.png

Why does the speed of memcpy() drop dramatically every 4KB?

On updating database in Entity Framework , Code first Migration, I am getting this error:

&gt; The ALTER TABLE statement conflicted with the FOREIGN KEY constraint &quot;FK_dbo.Clients_dbo.MedicalGroups_MedicalGroupId&quot;. The conflict occurred in database &quot;hrbc&quot;, table &quot;dbo.MedicalGroups&quot;, column &#39;Id&#39;.

This is my class:

    public partial class Client
    {
        [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int Id { get; set; }

        public string FirstName { get; set; }
        public string LastName { get; set; }
        public int? MedicalGroupId { get; set; }
        [ForeignKey(&quot;MedicalGroupId&quot;)]
        public virtual MedicalGroups MedicalGroup { get { return _MedicalGroup; } set { _MedicalGroup = value; } }
    }

Here is my 2nd class:

    public partial class MedicalGroups
    {
        [Key]
        public int Id { get; set; }
        public string Name { get; set; }
    }

And this is my migration which I am trying to apply:

    public override void Up()
    {
        AddForeignKey(&quot;dbo.Clients&quot;, &quot;MedicalGroupId&quot;, &quot;dbo.MedicalGroups&quot;, &quot;Id&quot;);
        CreateIndex(&quot;dbo.Clients&quot;, &quot;MedicalGroupId&quot;);
    }

Entity Framework The ALTER TABLE statement conflicted with the FOREIGN KEY constraint

I need help on my Excel sheet. How can I declare the following `IF` condition properly?


    if A1 = &quot;n/a&quot; then C1 = B1
    else if A1 != &quot;n/a&quot; or has value(int) then C1 = A1*B1

Using &quot;If cell contains #N/A&quot; as a formula condition.

I need help on my Excel sheet. How can I declare the following <code>IF</code> condition properly?
<pre><code class="hljs language-java">if A1 = "n/a" then C1 = B1
else if A1 != "n/a" or has value(int) then C1 = A1*B1
</code></pre>

How do you save output of a MySQL query to a MS Excel sheet?

Even if it&#39;s only possible to store the data in a `.txt` file, it will be okay.

How to save MySQL query output to excel or .txt file?

I use `Excel 2013` and `Power View` and `SQL Server 2008 R2`.

After create my `Data Source` and my `chart` in `Excel` When I want save my Excel file I get this message

    be careful parts of your document may include personal information 
    that cannot be removed by the Document Inspector.

What is this warning and how I can remove this message?
What are `personal information` that exist in my `Excel File`.

![enter image description here][1]


  [1]: http://i.stack.imgur.com/B7NS7.png

be careful parts of your document may include personal information that cannot be removed by the Document Inspector

It seem simple but I cannot find a way to define a range that goes up to the end of the column in an Excel formula.

For instance I can use this equation SUM(C:C) to sum all number found on the column C. However, given that the top of the page has titles and column headers, I would like to start my range at line 6. I thought SUM(C6:C) would do it but it does not work in Excel.

This is required so my SUM is always right no matter how many lines of data I add to my document in the future.

Thanks.

Sum up a column from a specific row down

I am working on angular js app and I stuck in a situation in which I have to export data to Xls using angular js. I have searched a lot on the internet for export functionality or any library for angular js so I can do that or at least I can get the idea how to export. I don&#39;t have any code or work to show here. 

 I need suggestions. Please help me on this. 

Thanks in advance.

Update:

I have a data which is an array of objects and I am iterating that on UI in a table. My backend is node.js and frontend are angular js.

My problem is if we have the data from the server and I am using on UI, how can I use the same data to export to Xls using angular js. I don&#39;t want to give a call again on the backend to extract the data and export that. 

In the existing table, the user can select the checkbox (Any number of rows or all rows) to extract the data to Xls.

In node.js I have used node module whose name is: Excel and it is available on nodemodules site.

My data is like that:

    &quot;data&quot;: [
        {
    		&quot;Name&quot;: &quot;ANC101&quot;,
    		&quot;Date&quot;: &quot;10/02/2014&quot;,
    		&quot;Terms&quot;: [&quot;samsung&quot;, &quot;nokia&quot;: &quot;apple&quot;]
    	},{
    		&quot;Name&quot;: &quot;ABC102&quot;,
    		&quot;Date&quot;: &quot;10/02/2014&quot;,
    		&quot;Terms&quot;: [&quot;motrolla&quot;, &quot;nokia&quot;: &quot;iPhone&quot;]
    	}
    ]

I want the solution using angularjs or any angularjs library.

Export to xls using angularjs

I am new to [epplus][1], and i&#39;m trying to read some values from an excel table.

This is what I have so far:

    var fileInfo = new FileInfo(filename);
    using(var excelPackage = new OfficeOpenXml.ExcelPackage(fileInfo))
    {
        foreach (var sheet in excelPackage.Workbook.Worksheets)
        {
            foreach (ExcelTable table in sheet.Tables)
            {
                 foreach(var row in table.Rows)  // &lt;-- !!
                 { ... }
            }
        }
    }


However, now I am stumped, as the `ExcelTable` only has a `Columns` property, but not a `Rows` property as I had expected. I cannot find a `Rows` property on any object in the library.

**How do I iterate through a table, reading Row for Row?**


  [1]: https://epplus.codeplex.com/

Content Type	Original Author	Original Content on Stackoverflow
Question	bobbyjones	View Question on Stackoverflow
Solution 1 - Excel	WitchGod	View Answer on Stackoverflow
Solution 2 - Excel	Micah Chaney	View Answer on Stackoverflow
Solution 3 - Excel	bto.rdz	View Answer on Stackoverflow
Solution 4 - Excel	barry houdini	View Answer on Stackoverflow
Solution 5 - Excel	cpbr	View Answer on Stackoverflow

Using "If cell contains #N/A" as a formula condition.

Excel Problem Overview

Excel Solutions

Solution 1 - Excel

Solution 2 - Excel

Solution 3 - Excel

Solution 4 - Excel

Solution 5 - Excel

Entity Framework The ALTER TABLE statement conflicted with the FOREIGN KEY constraint

Why does the speed of memcpy() drop dramatically every 4KB?

Attributions