I am writing a function to display a graph with multiple lines. Each line represents a column in my numpy array. My x-axis is the variable year and my y-axis is my np.array. I am struggling to find the right place to insert the nested list coorectly in the code to show the line of each field on the graph depending of the year

year = [2000,2001,2002,2003]
notes = [[10,11,11,14],[11,14,15,16],[15,14,12,11],[14,11,10,14]]
legend = {'maths':1, 'philosophy': 2, 'english': 3, 'biology': 4}

def PlotData (data,legend):
    for i in data:
        plt.plot(i,color = 'red' , marker = '.', 
                 markersize = 10, linestyle = 'solid')
        plt.legend(legend,loc ='upper left')
        plt.title('Final Examination')
        plt.xlabel('Year')
        plt.ylabel('Marks')
        plt.show()

PlotData((year,notes), legend)

CodePudding user response：

You first need to separate the x-axis from y-axis, because you have only have 1 array for x and multiple for y.

year, notes = data

Then you need to actually specify the x-axis in your code by adding year before i.

plt.plot(year, i , marker = '.', 
                 markersize = 10, linestyle = 'solid')

lastly you need to move the rest of the code outside of the loop since it only needs to be executed once.

• i removed the color=red to make the graph more clear with multiple colors.

year = [2000,2001,2002,2003]
notes = [[10,11,11,14],[11,14,15,16],[15,14,12,11],[14,11,10,14]]
legend = {'maths':1, 'philosophy': 2, 'english': 3, 'biology': 4}

def PlotData (data,legend):
    year, notes = data
    for i in notes:
        plt.plot(year, i , marker = '.', 
                 markersize = 10, linestyle = 'solid')
    plt.legend(legend,loc ='upper left')
    plt.title('Final Examination')
    plt.xlabel('Year')
    plt.ylabel('Marks')
    plt.show()

PlotData((year,notes), legend)

result: