Skip to main content

01. Syntax and Variables

8/28/26About 11 minAbout 1582 words

01. Syntax and Variables

Variables

Exercise 1 — Choose a variable name

For each piece of information, choose a suitable Python variable name.

  1. The hostname of a server
  2. The IP address of a server
  3. The number of connected users
  4. The temperature of a server room
  5. Whether a server is running
  6. The name of a network interface

Exercise 2 — Valid or invalid?

Which of the following are valid Python variable names?

  1. server_name
  2. server-name
  3. server1
  4. 1server
  5. ServerName
  6. server name
  7. _server
  8. server_name_2
  9. class
  10. ip_address

Exercise 3 — Create some variables

Write a script and create variables containing the following information:

  • The hostname webserver01
  • The IP address 192.168.1.20
  • The number of CPU cores: 8
  • Whether the server is running: True

Print all the information in a label-like way.

Exercise 4 — Spot the problem

What is wrong with the following code?

server-name = "web01"
ip address = "10.0.0.20"
1server = "server01"

Rewrite the code so that it works.

Exercise 5 — Variable or value?

Look at the following code:

hostname = "server01"
port = 22

For each item, indicate whether it is a variable name or a value:

  1. hostname
  2. "server01"
  3. port
  4. 22

Exercise 6 — Which code is better?

Both examples work. Which one would you prefer?

A

a = "web01"
b = "192.168.1.20"
c = 443

B

hostname = "web01"
ip_address = "192.168.1.20"
https_port = 443

Explain your choice.

Exercise 7 — A small mistake

A student wrote:

server_name = "web01"
server_ip = 192.168.1.20

What is wrong with the second line?

Correct the code.

Data types

Exercise 1 — What type is it?

What type does each variable contain?

hostname = "web01"
port = 443
temperature = 21.5
online = True

For each variable, write down its type (on paper with a pen).

Then use the type() function and print() to check your answers.

Exercise 2 — Server calculations

A server has the following specifications:

ram = 32
used_ram = 19
cpus = 8

Write Python code that prints:

  1. The amount of free RAM.
  2. The percentage of RAM that is currently used.
  3. The number of CPUs after adding 2 CPUs.

Your output should look something like:

Free RAM: 13 GB
RAM used: 59.375%
CPUs after upgrade: 10

Use f-strings for the output.

Exercise 3 — Working with hostnames

Create the following variable:

hostname = "  webserver01  "

Write code that prints:

  1. The hostname without the spaces around it.
  2. The hostname in uppercase.
  3. The hostname in lowercase.
  4. The length of the hostname.
  5. The hostname with "web" replaced by "app".

Use the appropriate string functions and operators.

Exercise 4 — Is this server suitable?

Consider the following variables:

os = "Linux"
ram = 16
online = True

A server is suitable for a particular application when:

  • it runs Linux,
  • it has at least 8 GB of RAM,
  • and it is online.

Create a Boolean expression that checks whether the server is suitable.

Print the result:

Server suitable: True

Then change one of the variables so that the result becomes False.

Exercise 5 — Data from a network device

A network device provides the following information as strings:

device_name = "switch01"
port_count = "24"
uptime_days = "37"
temperature = "31.5"

Convert the appropriate values to useful types.

Then print:

Switch: switch01
Ports: 24
Uptime: 37 days
Temperature: 31.5 C

Finally, calculate how many hours the device has been running and print that value as well.

Hint: You will need casting and a mathematical operator.

Exercise 6 — Working with an IP address

Consider:

ip_address = "192.168.10.25"

Write code that prints:

  1. The first character of the IP address.
  2. The last character of the IP address.
  3. Whether "168" occurs in the IP address.
  4. The length of the IP address.

Then print all this information using f-strings.

Exercise 7 — User input from a monitoring system

A monitoring system gives you these values:

cpu_load = "75"
disk_free = "42.5"
server_online = "True"

All three values are strings.

Convert them to the appropriate types and print:

CPU load: 75%
Free disk space: 42.5 GB
Server online: True

Then use a Boolean expression to check whether the server has:

  • less than 80% CPU load,
  • more than 20 GB free disk space,
  • and is online.

Print the result.

Exercise 8 — String manipulation

A server administrator entered the following hostname:

hostname = "  WEB-SERVER-01  "

Create a cleaned-up version of the hostname that:

  • has no spaces at the beginning or end;
  • is written in lowercase;
  • uses _ instead of -.

Print the result.

The expected output is:

web_server_01

Exercise 9 — What will Python do?

What happens when you run each of these?

print(10 + 5)
print("10" + "5")
print(10 + "5")
print(10 * 5)
print("10" * 5)

For each line:

  1. Write down the output, or
  2. Write down Error if Python produces an error.

Then explain why the results are different.

First admin script

Exercise 1 — Server information

Ask the user for:

  • the server hostname
  • the server IP address
  • the SSH port

The user should be able to enter the information themselves.

Print the result in this format:

Server: web01
IP: 192.168.1.20
SSH: 22

Use one print() statement with multiple parameters and sep.

Exercise 2 — Network address

Ask the user to enter:

  • a network address, for example 192.168.10.0
  • a subnet mask, for example 24

The subnet mask should be converted to an integer.

Print the result like this:

Network: 192.168.10.0/24

Then print the following on one line, separated by ->:

Network -> 192.168.10.0 -> Mask -> 24

Use multiple parameters with print() and sep.

Exercise 3 — Server startup message

Ask the user for:

  • the hostname of the server
  • the number of CPUs
  • the amount of RAM in GB

Convert the number of CPUs and the amount of RAM to integers.

Print a startup message where each piece of information is printed separately, without automatically moving to a new line.

For example:

Starting server web01... CPUs: 8... RAM: 16 GB... DONE!

Use:

  • input()
  • casting
  • print() with multiple parameters
  • sep
  • end

Do not use a single f-string for the complete message.

Exercise 4 — Server status

Write a program that asks the user for:

  • the server hostname
  • the server IP address
  • the number of CPU cores
  • the amount of RAM in GB
  • whether the server is online (True or False)

Convert the CPU cores, RAM, and online status to the appropriate types.

Print a status report similar to:

Server: web01
IP address: 192.168.1.20
CPU cores: 8
RAM: 16 GB
Online: True

Then print whether the server is considered powerful.

A server is powerful when it has at least 8 CPU cores and at least 16 GB of RAM.

Use a Boolean expression to determine this.

Exercise 5 — Network device information

Write a program that asks the user for:

  • the name of a network device
  • its IP address
  • the number of ports
  • its temperature in degrees Celsius

The number of ports and temperature should be converted to numbers.

Print the information using multiple parameters and sep:

Device-switch01-IP-192.168.1.2-Ports-24-Temperature-32.5C

Then print:

Temperature OK: True

A temperature is OK when it is below 40°C.

Finally, print the device name in uppercase and lowercase.

Exercise 6 — Login information

Write a program that asks the user for:

  • a username
  • a password
  • the number of login attempts

The username may contain spaces at the beginning or end. Remove these spaces and convert the username to lowercase.

Convert the number of login attempts to an integer.

Print:

Username: admin
Login attempts: 3

Then check whether the login should be allowed.

The login is allowed when:

  • the username is "admin"
  • and the number of login attempts is less than 5.

Print:

Login allowed: True

Use a Boolean expression for the check.

Exercise 7 — Server backup

Write a program that asks the user for:

  • the hostname of a server
  • the amount of data that needs to be backed up in GB
  • the available backup space in GB

Convert the two sizes to numbers.

Print a message showing the server and the backup sizes.

Then determine whether there is enough space for the backup.

There is enough space when the available backup space is greater than or equal to the amount of data.

Print:

Backup server: backup01
Data to backup: 125 GB
Available space: 200 GB
Enough space: True

Also print the amount of space that will remain after the backup.

Use an f-string for the first report and multiple parameters with sep for a second line:

Backup -> backup01 -> OK

Use end so that the words Checking backup... and DONE appear on the same line.

Exercise 8 — Mini server checker

Write a program that asks the user for:

  • a server hostname
  • a server IP address
  • the operating system
  • the number of CPU cores
  • the amount of RAM in GB
  • the server temperature
  • whether the server is online

Clean up the hostname using strip() and lower().

Convert the CPU cores, RAM and temperature to numbers. Convert the online status to a Boolean.

Print a report containing all the information.

Then check the following:

A server is ready for production when:

  • it is online;
  • it has at least 4 CPU cores;
  • it has at least 8 GB RAM;
  • its temperature is below 70°C;
  • and its operating system is either "linux" or "windows".

Print:

Production ready: True

Finally, print the hostname, IP address and operating system on one line, separated by |.

Last Updated:
Contributors: Sebastiaan Henau,Jochen Mariën