Interpret basic Python components and scripts

📘CCNP Encore (350-401-ENCORE-v1.1)

1. Why Python Is in the CCNP ENCOR Exam

Cisco includes Python in the ENCOR exam because:

Modern networks are programmable
Network devices support APIs and automation
Python is widely used to:
- Automate configuration
- Collect device data
- Validate network states
- Interact with controllers (like Cisco DNA Center)

👉 You are NOT expected to be a Python developer
👉 You ARE expected to read and understand basic Python scripts

The keyword in the exam blueprint is “Interpret”, not “Write complex code”.

2. What a Python Script Is

A Python script is a text file that contains Python commands and ends with:

.py

Example:

backup_config.py
check_interfaces.py

A Python script:

Is executed line by line
Runs from top to bottom
Stops if it hits an error (unless handled)

In networking, scripts are used to:

Read device information
Send commands
Process outputs
Make decisions automatically

3. Basic Python Syntax Rules (Exam Important)

3.1 Indentation (Very Important)

Python uses indentation to define blocks of code.

Example:

if status == "up":
    print("Interface is up")

Spaces at the beginning of the line matter
Usually 4 spaces
No curly braces { } like other languages

❗ Wrong indentation = script fails

3.2 Comments

Comments explain the code and are ignored when running.

Single-line comment:

# This script checks device status

Comments are useful for:

Documentation
Understanding scripts in exams

4. Variables

A variable stores data in memory.

Example:

hostname = "Router1"

No need to declare data type
Python decides automatically

Common variable naming rules:

Letters, numbers, underscores
Cannot start with a number
Case-sensitive

Example:

device_ip = "192.168.1.1"

5. Data Types (Exam Critical)

5.1 String (Text)

Text values are strings.

device_name = "Switch1"

Enclosed in quotes
Used for:
- Hostnames
- IP addresses
- Commands

5.2 Integer (Whole Numbers)

port = 22

Used for:

VLAN IDs
Port numbers
Counters

5.3 Float (Decimal Numbers)

cpu_usage = 12.5

Used for:

Percentages
Timers
Measurements

5.4 Boolean (True or False)

status = True

Used for:

Conditions
Validation
Decision-making

6. Lists

A list stores multiple values in one variable.

devices = ["Router1", "Router2", "Switch1"]

Ordered
Index starts at 0

Access items:

devices[0]

Lists are used for:

Device inventories
Interface lists
IP address collections

7. Dictionaries (Very Important for Networking)

A dictionary stores data as key-value pairs.

device = {
    "hostname": "Router1",
    "ip": "192.168.1.1",
    "os": "IOS-XE"
}

Access value:

device["ip"]

Used heavily in:

API responses
JSON data
Network configurations

8. Operators

8.1 Assignment Operator

x = 10

8.2 Comparison Operators

Used in conditions.

Operator	Meaning
==	Equal
!=	Not equal
>	Greater than
<	Less than

Example:

if cpu > 80:
    print("High CPU")

8.3 Logical Operators

Operator	Meaning
and	Both conditions true
or	One condition true
not	Reverse condition

Example:

if status == "up" and admin == "enabled":

9. Conditional Statements (if, elif, else)

Used to make decisions.

if status == "up":
    print("Interface is operational")
elif status == "down":
    print("Interface is down")
else:
    print("Unknown state")

Used for:

Checking interface state
Validating configuration
Handling errors

10. Loops

Loops repeat actions.

10.1 for Loop

Used when you know how many times to repeat.

for device in devices:
    print(device)

Used for:

Looping through devices
Checking interfaces
Applying configuration

10.2 while Loop

Runs while a condition is true.

while attempts < 3:
    attempts += 1

Used for:

Retry logic
Waiting for responses

11. Functions

A function is reusable code.

def check_status():
    print("Checking status")

Call function:

check_status()

Functions help:

Organize code
Avoid repetition
Improve readability

12. Input and Output

12.1 Printing Output

print("Configuration applied")

Used to:

Show results
Display messages
Debug scripts

12.2 User Input

ip = input("Enter IP address: ")

Input is always a string.

13. Importing Modules

Modules add extra functionality.

import json

Or:

from datetime import datetime

In networking:

json → API data
requests → REST APIs
time → delays

You don’t need to know deep module usage—just recognize imports.

14. Error Handling (try / except)

Used to prevent script crashes.

try:
    print(int("abc"))
except:
    print("Error occurred")

Used for:

API failures
Connection issues
Invalid input

15. Reading and Interpreting a Python Script (Exam Skill)

You should be able to:

Identify variables
Understand loops
Predict output
Identify errors
Understand logic flow

Example:

devices = ["R1", "R2"]

for d in devices:
    print(d)

Output:

R1
R2

16. Python and Networking Context (Exam Relevant)

Python is used with:

REST APIs
Controllers
Automation frameworks
Device configuration tools

You do not need to:

Write full automation scripts
Memorize libraries
Build applications

You must:

Understand script structure
Interpret logic
Read code confidently

17. Exam Key Takeaways (Very Important)

✔ Understand basic Python syntax
✔ Know variables and data types
✔ Understand lists and dictionaries
✔ Read loops and conditions
✔ Interpret simple scripts
✔ Understand Python’s role in network automation

18. Simple Summary

Python in CCNP ENCOR is about understanding, not programming expertise.