I am trying to get the derivative of this CSV data set, and this is code I have so far I thought it would be similar to this matlab code:

```
dy=diff(y)./diff(x)
plot(x(2:end),dy)
```

This is my attempt at the code:

```
import csv
data = list( csv.reader(open('C:/images/TEST1.txt','rU')) )
data = map(lambda x: [float(x[0]),float(x[1])],data)
P = list_plot(data, plotjoined= True, color = 'blue', xmin = 0, xmax = 3)
TeraHertz = text('Tera Hertz', (1.5,-.9))
Absorbance = text('Absorbance', (0.8,5))
g = P + TeraHertz + Absorbance
g.show()
latex(g)
g.save('TeraHertzTEST1.pgf')
t=diff(x[1]).diff(x[0])
l = plot(x[0],t)
l.show()
```