11. Importing the Dataset

IMPORTING THE DATASET

Spyder IDE Activity in Python

• Ensure that your dataset resides where your python file is.

• So inside Spyder IDE, press on file explorer on the right side

• Navigate to the folder that contains Data.csv

• For Mac users, after navigating to the correct directory, you have an option on the right hand side to set that as working directory.

• For Windows users, just ensure that you import the correct data set from your woking Python file location.

• If you press F5, you will set your working directory while running the Python file at the same time.

    #Importing the Dataset
    dataset = pd.read_csv("Data.csv")

• If you press Ctrl and Enter, on that specific line, if there is an output of dataset = pd.read_csv("Data.csv") on IPython console, it means the Dataset is successfully imported.

• Press on variable explorer and double click on the Dataset to view the full set of data

• On Dataset, the index starts from 0.

Changing the format of the Salary Column

• To change the decimal place of values of salary to display no decimal place after the 0, and the value to a Float.

• Press on format inside the view Dataset. and input this,

    %.of

• In Machine Learning, in a Dataset we need to distinguish the matrix of features and the independent variable vector.

Creating a matrix of 3 Independent Variables

• So right now, we are going to create a matrix of the three independent variables.

    X = dataset.iloc[:, :-1].values

• : means that we take all the lines, because whats on the left means the lines which is the rows of the Dataset

• Whats on the right of the comma, means the other columns

• :-1 means we take all of the columns except the last one

• .values means that we want to take all the values and that just the Python syntax and how it works

• Select the line and execute

• If you type X in the IPython console, you should see that we have our data from the first three columns

Creating the Dependent Variable Vector

    Y = dataset.iloc[:, 3].values

• The index 3 represents the last column of Purchased for Dependent Variable

Importing the Dataset in Rs

• To set the working directory in RStudio, click on Browse on Files, and click on ... to go to your working directory

• Click on More, and select Set As Working Directory

    # Data Preprocessing
  
    # Importing the dataset
    dataset = read.csv("Data.csv")

• Press Ctrl enter to execute and double click on the Data, and you should display the dataset.

• For R, the first observations start at 1 here and end at 10.