Python Function Tutorial – Part IV


Visit: QuantInsti

See Part IPart II  and Part III of this installment to learn more about Python functions.

Python functions with a single argument

A function can be called as many times as we want, and Python will execute the statements within its body. The Python function we mentioned above, neither takes any input nor does it return any output. It just prints the statement written within it. If the function has to take any input, it goes within the parentheses as a parameter during the function definition. Parameters are the values we supply to the function so that the function can do something utilizing those values.

Note the terminology used here:

  • Parameters: They are specified within parentheses in the function definition, separated by commas.
  • Arguments: When we call a Python function, values that parameters take are to be given as arguments in a comma separated format.

The modified version of the above simple Python function explains these two terms:

# Here ‘person_name’ is a parameter.
def greet(person_name):
“””Prints greetings along with the value received via the parameter.”””
print(‘Hello ‘ + person_name + ‘!’)

The above function definition defines person_name as a parameter to the function greet, and it can be called as shown below:

# Calling the function

The above call to the function greet takes a string Amigo as an argument and the output will be as follows:

Hello Amigo!

In the next installment, the author will discuss Python functions with multiple arguments and a return statement.

Visit for ready-to-use Python functions as applied in trading and data analysis.

Disclosure: Interactive Brokers

Information posted on IBKR Traders’ Insight that is provided by third-parties and not by Interactive Brokers does NOT constitute a recommendation by Interactive Brokers that you should contract for the services of that third party. Third-party participants who contribute to IBKR Traders’ Insight are independent of Interactive Brokers and Interactive Brokers does not make any representations or warranties concerning the services offered, their past or future performance, or the accuracy of the information provided by the third party. Past performance is no guarantee of future results.

This material is from QuantInsti and is being posted with permission from QuantInsti. The views expressed in this material are solely those of the author and/or QuantInsti and IBKR is not endorsing or recommending any investment or trading discussed in the material. This material is not and should not be construed as an offer to sell or the solicitation of an offer to buy any security. To the extent that this material discusses general market activity, industry or sector trends or other broad based economic or political conditions, it should not be construed as research or investment advice. To the extent that it includes references to specific securities, commodities, currencies, or other instruments, those references do not constitute a recommendation to buy, sell or hold such security. This material does not and is not intended to take into account the particular financial conditions, investment objectives or requirements of individual customers. Before acting on this material, you should consider whether it is suitable for your particular circumstances and, as necessary, seek professional advice.

In accordance with EU regulation: The statements in this document shall not be considered as an objective or independent explanation of the matters. Please note that this document (a) has not been prepared in accordance with legal requirements designed to promote the independence of investment research, and (b) is not subject to any prohibition on dealing ahead of the dissemination or publication of investment research.

Any trading symbols displayed are for illustrative purposes only and are not intended to portray recommendations.