How can I use Python's `timeit` module to measure the execution time of code segments?

Measuring Code Execution Time Using Pythons timeit

In Python, quantifying the execution duration of code segments is crucial for performance testing. This article explores how to leverage Pythons timeit module for this task.

Example Use Case

Consider the following Python script that executes multiple queries on a database:

<code class="python">conn = ibm_db.pconnect("dsn=myDB", "usrname", "secretPWD")
for r in range(5):
    print "Run %s\n" % r
    query_stmt = ibm_db.prepare(conn, update)
    ibm_db.execute(query_stmt)
ibm_db.close(conn)</code>

To measure the execution time of the queries, we can employ Pythons timeit module.

Using timeit

Step 1: Import the timeit Module

<code class="python">import timeit</code>

Step 2: Define the Code to Time

Create a string or function that encapsulates the code whose execution time needs to be measured:

<code class="python">setup_code = """
import ibm_db
conn = ibm_db.pconnect("dsn=myDB","usrname","secretPWD")
query_stmt = ibm_db.prepare(conn, update)
"""

code_to_time = """
ibm_db.execute(query_stmt)
"""</code>

Step 3: Set Configuration Parameters

Specify the number of repetitions and iterations for the timeit function:

<code class="python">repetitions = 5
iterations = 100</code>

Step 4: Measure the Execution Time

<code class="python">timeit_result = timeit.timeit(code_to_time, setup=setup_code, number=iterations, globals=globals())</code>

Step 5: Output the Result

<code class="python">print("Execution time:", timeit_result)</code>

Additional Considerations

• For precise measurements, ensure that the code to be timed executes multiple times during the iteration.
• For fine-grained timing on Linux, use time.clock() instead of time.time().
• Pythons timeit provides options for setting different timers and managing repeat setup, enabling customization for specific needs.

By following these steps, you can accurately time code segments in your Python scripts and gain insights into their performance characteristics.

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