Computation for Linguists

Beginning Python: Value Types

Dr. Andrew M. Byrd

2025-10-01

Review

  • What did you learn last time?

Review

  • Running python:
    • Terminal
    • Stand-alone .py file
    • Quarto doc (qmd)
  • Starter python skills:
    • print()
    • basic math (+, -)
    • assigning variables with =

Value Types

Three basic value types

  1. Numbers
  2. Strings
  3. Booleans (logical values)
  • You can check something’s type using the type() function

Numbers

Two types:

  • int: integers (no decimals)
num_1 = 1
type(num_1)
  • float: floating point numbers (decimals)
num_2 = 1.5
type(num_2)

Number Operators

We’ve seen two operators already:

  • x + y (add)
  • x - y (subtract)

Number Operators

Here are two more:

  • x * y (multiply)
  • x / y (divide)

Operator Activity:

  • Using python, compute the following equations:
  1. 100 - 37
  2. 4 x 80
  3. 100 ÷ 25

Number Operators: Exponent

Operators:

  • x ** y (exponent)
2 ** 2 == 2 * 2

Number Operators: Modulus

  • x % y (modulus: remainder)
10 % 3 == 1   # 3 goes into 10 three times, remainder 1
14 % 5 == 4   # 5 goes into 14 twice, remainder 4

Number Operators: Modulus

  • The modulus command is actually quite useful, as it shows us when one number is not evenly divisible by another.
n = 17
if n % 2 == 0:
    print("even")
else:
    print("odd")

Number Operators: Floor Division

  • x // y (floor division)
10 // 3   # 3  (3 goes into 10 three times, remainder dropped)
14 // 5   # 2  (5 goes into 14 two times, remainder dropped)
  • This is a way of rounding down, resulting in an integer
  • Note: there’s no built-in way to round up – you’ll have to do that in other ways

Summing up “Divisive” Operators:

14 / 5      # 2.8 (normal division)
14 % 5      # 4   (modulus)
14 // 5     # 2   (floor division)

Operator Activity

  1. Divide 100 by 9 three different ways:

    • Normal division /
    • Floor division (rounding down) //
    • Modulus %

  2. How many full weeks and leftover days are in a full year?

Strings

Three basic value types

  1. Numbers
  2. Strings
  3. Booleans (logical values)
  • You can check something’s type using the type() function

Strings

If you type text without quotes:

Andrew
# NameError
  • Why does it do this?

Strings

  • If we assign Andrew as having the value “Andrew”…
>>> Andrew = "Andrew"
>>> Andrew
'Andrew'

Strings

With quotes:

>>> "Andrew"
'Andrew'
>>> 'Andrew'
'Andrew'

Strings

Assigning strings:

title = "Dr."
first_name = "Andrew"
last_name = "Byrd"

Strings

Concatenate with +:

title + first_name + last_name
  • What happens when we print the three?
  • How might we improve the output?

Strings

We could also print it this way:

print(title, first_name, last_name)

Strings

What happens when we run this code?

print("I said, "Hello!"")

Strings

  • For this, we’ll need to have a character \".
    • Cf. LaTeX \#, etc.
"I said, \"Hello!\""
  • Besides " (and '), almost any character can be within a string.

Boolean (Logical) Values

Three basic value types

  1. Numbers
  2. Strings
  3. Booleans (logical values)
  • You can check something’s type using the type() function

Boolean (Logical) Values

Only two: True, False.

Usually created by comparisons:

first_name == "Bob"
# False

Important!

  • = means variable assignment
  • == means equals or testing if two things are equal

Comparison Operators

  • == is exactly equal to
  • != is not equal to
  • > greater than
  • >= greater than or equal to
  • < less than
  • <= less than or equal to

Logical Operators

  • not flips a boolean
  • and is true if both are true
  • or is true if at least one is true

Examples

Check for Andrew with “w” or without:

(first_name == "Andrew") or (first_name == "Andre")

Check for Andrew, who is 46:

(first_name == "Andrew") and (my_age == 46)

Check for Andrew, who is not 45:

(first_name == "Andrew") and not (my_age == 45)

Activity

Activity: Predicting Aspiration

  • In English, voiceless stops (p, t, k) are usually aspirated when they occur at the beginning of a word.
  • Your task: write a small Python script that predicts whether the first sound in a word will be aspirated.

Activity: Predicting Aspiration

Steps:

  1. Assign a word like “pin”, “spin” to a variable called word.
    • To identify the first character, use word[0].
  2. Create three variables: starts_p, starts_t, starts_k
    • starts_p = word[0] == "p", etc.
  3. Create another variable aspirated, whose value is True if any of the above is True.
    • Hint: combine them with or
  4. Print out the word and whether it is aspirated.

Activity Answers

Answers

word = "pin"   # try: "spin", "top", "stop", "cat", "skat"

# Step 1: check if word starts with a voiceless stop
starts_p = word[0] == "p"
starts_t = word[0] == "t"
starts_k = word[0] == "k"

# Step 2: decide aspiration (simplified: only if it’s the first sound)
aspirated = starts_p or starts_t or starts_k

print("Word:", word)
print("Aspirated?", aspirated)

Broadening the Script

But what if we want to test any word?

  • First, input this in the Terminal:
word = input("Enter a word, any word: ")
  • Then:
# Step 1: check if word starts with a voiceless stop
starts_p = word[0] == "p"
starts_t = word[0] == "t"
starts_k = word[0] == "k"

# Step 2: decide aspiration (simplified: only if it’s the first sound)
aspirated = starts_p or starts_t or starts_k

print("Word:", word)
print("Aspirated?", aspirated)