Create A Calculated Field

data science tableau calculated field

I have just enrolled in a Data Science course on Udemy  and I learned good stuff.

Now is the time to solve the problem of who is winning the bonus.

The first thing to do is clean the dashboard. To do this, click on the « Clear Sheet » button.

data science tableau calculated field

To start we need to create a « Bar Chart » to see the salesperson. In this data, salesperson named « Rep » for representatives.

data science tableau calculated field

To see how many items were sold by each sales representative, you need to put « Rep » in « Columns » and « Units » in « Rows ».

data science tableau calculated field

You can see that the representative who sold the most is Richard.

But we want to have more details. We need to know who is the best representative by region and for now, we can’t see that.

To see this, you put « Region » in « Columns » before « Rep ».

data science tableau calculated field

As you can see, the « Bar Chart » changed. There are separations by region.

In each region, you can see the representatives and the number of items they sold. Alex is the best in Central. Richard is the best in the East and James is the best in West.

To get better visibility, you can order the bars in descending order. Move the mouse over the label « Units » of the bar chart and an icon will apprear. Click on it and the bars will be sorted in descending order.

data science tableau calculated field

Unfortunately, we didn’t answer the question because « Units » is only the number of items sold. What interests us is the amount of money earned by selling the product but we don’t have this type of measure. There is no measure that shows us the total value of sales. There are only « Units » and « Units Price ».

In this case, you have to make a calculation to have the total sales in cash. For each representative, you need to multiply « Units » with « Units Price ».

Let’s look at the data to make a test calculation. Right-click on the « OfficeSupplies » data and click on « View Data ». For example, you see that Nick sold 29 binders to $1.99. So 29 (Units) multiplied by 1.99 (Unit Price) equals $57.71 for this sale.

data science tableau calculated field data science tableau calculated field

In our data, we have no measure where « Units » is multiplied by « Units Price ».

data science tableau calculated field

To solve this problem, you will create an additional measure with a « Calculated Field ». « Calculated Field » si an element that allows us to create measures by calculating quantities.

To create this, right-click in the « Measure » zone and select « Create calculated field… ».

data science tableau calculated field

You can name the calcultated field « TotalSales »

data science tableau calculated field

Select « Units » uses the « * » sign to multiply and select « Unit Price » and click « OK ».

data science tableau calculated field data science tableau calculated field

Now, you can see that your measure « TotalSales » in the « Measure » zone.

data science tableau calculated field

By looking good, you can see that there is an « = » sign before the « # ». This is to indicate that this measure is a calculated field.

Ok, the measure is ready, let’s go. Put « TotalSales » on « Units » to replace « Units » with « TotalSales. Tableau automatically takes the sum aggregate.

data science tableau calculated field

If you want to do this more cleanly, you can remove « Units » by dragging it outside « Rows », then take « TotalSales » and put it in « Rows ».

data science tableau calculated field data science tableau calculated field

Now, that we have a « Bar Chart » with data from « TotalSales », we sort the bars in descending order by clicking here.

data science tableau calculated field data science tableau calculated field

As you can see, the results are different because Richard is no longer the best representatives in the East, it’s Suzanne. The best representative in the East is Suzanne, the best representative at the Center is Mathiew and the best representative in the West is still James.

it’s with the calculated field « TotalSales » that we can know who are the best representatives by region so Suzanne, Mathiew and James earn a bonus.

This was an example to learn how to create a calculated field in Tableau. Have fun creating new calculated field to master this tool that is really useful.

Share this article if you think it can help someone you know. Thank you.

-Steph

Navigate In Tableau

front boat

I have just enrolled in a Data Science course on Udemy  and I learned good stuff.

We’ll explore Tableau’s tools

From the connection manager, we’ll go into the Tableau’s workspace.

Click on the « Sheet1 » tab at the bottom of the window.

data science tableau screenshot

Here is the Tableau’s workspace.

data science tableau screenshot

The 2 important elements of the workspace are « Data » on the left and the workspace on the right. It’s in the workspace that you’ll create tables and charts.

We’ll start with « Data » on the left.

data science tableau screenshot

« Data » divided into 2 zones : dimensions and measures.

The dimensions and measures are 2 different rules that will allow you to manipulate data.

Tableau sets the numerical values in « measures » and the categorical or quantitative variables in « dimension ». This is the Tableau’s settings by default.

There is also another way to explain « dimension » and « measures ». The « dimensions » are independent variables and the « measures » are dependent variables.

For exemple, « Units » is a measure, it’s the number of items sold per product. « Region » is a dimension, it’s the geographic region where the product sold. With 2 elements we can know how many items sold by region. This means that « Region » is an independent variable and « Units » is a dependent variable because it will be grouped by region.

But if you don’t like it, you can move the entities between dimension and measures and the opposite by click and drag.

In the menu bar, at the top, there is « File » where you can open and save file.

data science tableau screenshot

« Data » to connect to new source files.

data science tableau screenshot

« Worksheet » is the workspace to create analyzes

data science tableau screenshot

« Dashboard » is a combination of worksheet

data science tableau screenshot

« Story » is a combination of worksheet and dashboard

data science tableau screenshot

« Analysis » to specify how you want to do your analysis on your workspace

data science tableau screenshot

« Map » to add maps to the workspace

data science tableau screenshot

« Format » contains formatting options

data science tableau screenshot

Now, let’s study the workspace.

In the workspace, the main elements are « Columns » and « Rows ». This is where you decide which data goes in columns and rows in your worksheet.

You can also choose different format for these elements like colors, size, text level of detail and tooltips (useful tool optional).

data science tableau screenshot

Let’s do a test. Use data from « Region » (which is in « dimension »). Move « Region » with a click and drop to the center of your workspace. Now, « Region » is in the element « Rows ».

A table appears in your workspace.

data science tableau screenshot

You put a dimension in your workspace. Now put a measure in your workspace.

Uses the « Units » data. Move « Units » with a click and drop next to the « Region » column.

data science tableau screenshot

As you can see, Tableau automatically put « Region » in the « Rows » element and the « Units » data aggregated by region. In this way, you can tell how many items were sold by region.

Now, what you can do is to move « SUM(Units) » to the « Columns » element.

data science tableau screenshot data science tableau screenshot

And then, you have a « bar chart » to see how many items have been sold by region. You can enlarge the graphic with a click and drop.

Let’s look at the tools that are in « Show Me » zone.

data science tableau screenshot

Click on « Pie chart » to have this chart’s type.

data science tableau screenshot

Click on « Size » icon and drag from left to right you can increase the chart’s size.

data science tableau screenshot

In this chart, each region has a color and proportion of items sold by region.

You can also test the « bubble chart ». Tableau organizes the data automatically and everything and placed in the « Marks ».

data science tableau screenshot

You can test « Treemaps » chart. This is the same principle as « bubble chart » but it’s rectangles instead of circles.

data science tableau screenshot

As you can see in « Show Me », there are charts disabled. This is because you need some elelments in your data to be able to activate them.

For example for the « Area chart », you need « date »data to activate it.

Share this article if you think it can help someone you know. Thank you.

-Steph

Connect Tableau Public To A CSV File

tableau connect file csv data science

I have just enrolled in a Data Science course on Udemy  and I learned good stuff.

After downloading the file « OfficeSupplies.csv », you will open this file with Tableau. When you open Tableau, there is a « Connect » column :

tableau connect file csv data science

Click on « Text File » and open the file « OfficeSupplies.csv » :

tableau connect file csv data science

The connection manager appears for this source file :

tableau connect file csv data science

At the top left, there is « Connect » where the file is located and below it, there is « File » with 1 file. There is 1 file because you imported 1 file. I’ll show you later how to import several files of the same type.

tableau connect file csv data science

In the center, there is a window with the files you connected. And it’s possible to connect several files.

tableau connect file csv data science

For exemple, if you do a drag and drop here, Tableau will try to connect these 2 files.

tableau connect file csv data science

You can work with data comes from several differents files, different tables from different CSV files. We’ll see that later.

At the bottom, there is a preview of the file with columns and rows. Colums « Order Date », « Region », « Rep » and « Items » identified as data in text format. Columns « Units » et « Unit Price » identified as data in number format.

tableau connect file csv data science

Now you’re gonna go on the dashboard. To access it, click here.

tableau connect file csv data science

Here is the dashboard. 

tableau connect file csv data science

We will discuss the various function in more detail in the next section.

Now, I just want to show you that we have « Data » column with our source file.

tableau connect file csv data science

If you do a right-click and click on « View Data », you see the data as in the previous window.

tableau connect file csv data science

tableau connect file csv data science

You’ve seen, it’s simple to connect a source file to Tableau.

Wait, I’ll show you how you can connect more source files. Click here to return to the connection manager where you can connect several different files.

tableau connect file csv data science

Of if you want to stay on the dashboard, you can click on the top left on « Data » then « New Data Source ».

tableau connect file csv data science

Or click on this icon on the dashboard. Here are the files types you can connect to Tableau

tableau connect file csv data science

What is interesting with the « Statistical File » is that we can connect files type SAS, SPSS and R.

tableau connect file csv data science

We have access to different server with OData and others.

tableau connect file csv data science

It’s perfect, now you can connect a data source to Tableau and you’ll see later how to connect data faster.

Share this article if you think it can help someone you know. Thank you.

-Steph

Explanation Of The Challenge And Data

challenge

I have just enrolled in a Data Science course on Udemy  and I learned good stuff.

This is the 1st challenge. Use your web browser to go to superdatascience website  to download a data set. In the « Part 1 Visualization » section, click on « Offices Supplies » to download the file « OfficeSupplies.csv ».

data csv file

To organize myself, I created a folder « Visualization » with 3 subfolders. Each subfolder corresponds to the section of « Visualization ». I put the data set « OfficeSupplies.csv » in the 1st subfolder.

data csv file

« OfficeSuplies.csv » is a CSV file. A CSV file is a text file that represents an table but the elements separated by comma.

You can open this CSV file with NotePad++  for PC or with Sublime Text  for Mac.

On the 1st line (column title), we see that we have 6 columns. Each column separated by a comma and the file contains 44 lines.

data csv file

You can also open a CSV file with Excel, OpenOffice  or LibreOffice  to have a table, which is easier to read.

To open a CSV file with Excel, here are the instructions :

  • Open a blank workbook

  • Go to Data tab

  • Click button « From Text » in the general external data section

  • Select your CSV file

  • Follow the Text Import Wizard (in step 2, select the delimiter of your text).

data csv file

This data set contains data from a store that sells office equipment :

  • Order date – date of sale

  • Region – The store is in 3 region (East, Central and West)

  • Rep – salesperson’s first name

  • Item – product’s name

  • Units – product’s quantity

  • Unit Price – price per unit

Each line shows how many sales there were for a product.

The challenge is to help the manager to know who made the most sales per region in the period of this data set. The period of this data set is from July 2014 to June 2015.

The person who made the most sales in each region has a bonus and there are 3 bonus so 1 bonus per region.

It’s will this challenge that we’ll use Tableau Public.

Share this article if you think it can help someone you know. Thank you.

-Steph