×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

#### Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

# Array used to look up a value in matrix

## Array used to look up a value in matrix

(OP)
I have attached a simple file to help illustrate my question. I have the array Wui that gives input values. I need these values to help create another array with the results from Weight_of_Unit. Is this even able to be done and if so, how?

Ryan Erick Broomé, S.E., P.E.

### RE: Array used to look up a value in matrix

Yes, Mathcad can do this quite easily using the one of the lookup functions, vlookup.

By default, Mathcad indexes arrays starting with zero for the first row or column. If you want to start with one instead, set the built-in ORIGIN to 1. You can either do this from the Tools/Worksheet Ooptions dialog box or you can set its value in the worksheet ... I prefer to do the latter as it makes it more obvious to others.

The function vlookup(z,m,c) looks for value z in the first column of array m and, for each row where it is found, returns the corresponding values in column c.

Note: in your original worksheet, you had A.i rather than A[i, hence the error as the range variable should (usually) appear on the left hand side of a definition if it's on the right hand side.

### RE: Array used to look up a value in matrix

lexcognito,

Note: in your original worksheet, you had A.i rather than A[i, hence the error as the range variable should (usually) appear on the left hand side of a definition if it's on the right hand side.

Wow! How did you figure that out??! Onscreen, those two look the same to me. Only after reading your post, did I try each one out, and you are correct. I'll have to remember this for future Mathcad work.

I give you a sar for that.

chichuck

### RE: Array used to look up a value in matrix

#### Quote (chichuck)

Note: in your original worksheet, you had A.i rather than A[i, hence the error as the range variable should (usually) appear on the left hand side of a definition if it's on the right hand side.

Wow! How did you figure that out??! Onscreen, those two look the same to me. Only after reading your post, did I try each one out, and you are correct. I'll have to remember this for future Mathcad work.

It's a common occurrence and quite easy to inadvertently type '.' instead of '[', so I tend to look for it when I see odd error messages. The trick is to click on an expression and you should note a slight flicker as Mathcad displays it as 'A.i' rather than 'Ai. In addition, the editing line is limited to just the A when it's a vector and the whole of A.i when its a subscripted name.

#### Quote:

I give you a sar for that.

Thanks.

### RE: Array used to look up a value in matrix

(OP)
Thanks so much for your help. That is exactly what I needed.

Ryan Erick Broomé, S.E., P.E.

### RE: Array used to look up a value in matrix

No worries.

#### Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

#### Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

#### Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a partâ€™s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

# Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!