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name: python-scala-syntax-mapping description: Reference guide for translating Python syntax constructs to Scala equivalents. Use when converting Python code to Scala and need mappings for basic syntax elements like variable declarations, control flow, comprehensions, string formatting, and common operators.

Python to Scala Syntax Mapping

Variable Declarations

Prefer val over var unless mutation is required.

Type Mappings

Control Flow

Conditionals

Copy# Python
if x > 0:
    result = "positive"
elif x < 0:
    result = "negative"
else:
    result = "zero"

Copy// Scala - if is an expression
val result = if (x > 0) "positive"
             else if (x < 0) "negative"
             else "zero"

Loops

Copy# Python for loop
for i in range(10):
    print(i)

for item in items:
    process(item)

for i, item in enumerate(items):
    print(f"{i}: {item}")

Copy// Scala equivalents
for (i <- 0 until 10) println(i)

for (item <- items) process(item)

for ((item, i) <- items.zipWithIndex) println(s"$i: $item")

While loops

Copy# Python
while condition:
    do_something()

Copy// Scala
while (condition) {
  doSomething()
}

Comprehensions

Copy# Python list comprehension
squares = [x ** 2 for x in range(10)]
evens = [x for x in numbers if x % 2 == 0]
pairs = [(x, y) for x in xs for y in ys]

Copy// Scala for-comprehensions or map/filter
val squares = (0 until 10).map(x => x * x).toList
val evens = numbers.filter(_ % 2 == 0)
val pairs = for { x <- xs; y <- ys } yield (x, y)

Functions

Copy# Python
def add(a: int, b: int) -> int:
    return a + b

# Lambda
square = lambda x: x ** 2

# Default arguments
def greet(name: str, greeting: str = "Hello") -> str:
    return f"{greeting}, {name}!"

Copy// Scala
def add(a: Int, b: Int): Int = a + b

// Lambda
val square: Int => Int = x => x * x
// or shorter: val square = (x: Int) => x * x

// Default arguments
def greet(name: String, greeting: String = "Hello"): String =
  s"$greeting, $name!"

String Formatting

Common Operators

Exception Handling

Copy# Python
try:
    result = risky_operation()
except ValueError as e:
    handle_error(e)
finally:
    cleanup()

Copy// Scala
import scala.util.{Try, Success, Failure}

// Pattern 1: try-catch
try {
  val result = riskyOperation()
} catch {
  case e: IllegalArgumentException => handleError(e)
} finally {
  cleanup()
}

// Pattern 2: Try monad (preferred for functional style)
val result = Try(riskyOperation()) match {
  case Success(value) => value
  case Failure(e) => handleError(e)
}

None/Null Handling

Copy# Python
if value is None:
    return default
return process(value)

# Or
result = value if value is not None else default

Copy// Scala - use Option
val result = optionValue match {
  case Some(v) => process(v)
  case None => default
}

// Or more concisely
val result = optionValue.map(process).getOrElse(default)