Book Image

Python for Finance

By : Yuxing Yan
Book Image

Python for Finance

By: Yuxing Yan

Overview of this book

Table of Contents (20 chapters)
Python for Finance
About the Author
About the Reviewers

Using keyboard commands to stop an infinitive loop

Sometimes, because of carelessness or other reasons, we might end up with an infinitive loop (refer to the following program). Our original intention is to print just four numbers ranging from one to four. However, since we forgot to add 1 to the variable i after each printing, the exit condition will never be satisfied, that is, it leads to an infinitive loop. For such cases, we could use Ctrl + C or Ctrl + Enter to stop such an infinitive loop:

While i<5:
    Print i

If these commands do not work, then use Ctrl + Alt + Del to launch the Task Manager, choose Python, and then click on End Task.

Estimating implied volatility by using a while loop

This time, we use the Black-Scholes-Merton put option model and a while loop to estimate the implied volatility. First, we present the put option model as follows:

def bs_put(S,X,T,rf,sigma):
    from scipy import log,exp,sqrt,stats