Author: saqibkhan

Swift If (Real-Life Examples)

Apply conditional logic to real situations like validation, feature flags, or permissions.

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Validate input with conditions

Use conditions to validate input and guard against empty or invalid values.

Example

let input = "hello"
if !input.isEmpty {
  print("Input received: \(input)")
}

When the input is empty, the code inside the condition is skipped.

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Feature Flag

Gate a feature behind a flag and a user group.

Example

let enabled = true
let userGroup = "beta"
if enabled && userGroup == "beta" {
  print("Show feature")
}

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Swift If with Logical Operators

Combine conditions with &&, ||, and negate with !.

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Combine conditions with logical operators

Use AND, OR, and NOT to build complex conditions that control code paths.

Example

let isMember = true
let hasCoupon = false
if isMember || hasCoupon {
  print("Discount applied")
}

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AND and NOT

Combine conditions with && and negate with !.

Example

let isMember = true
let expired = false
if isMember && !expired {
  print("Active member")
}

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Swift Nested If

Nest if statements to check multiple levels of conditions.

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Use nested conditions for multi-step checks

Use nested conditions to handle layered checks, such as authentication then role.

Example

let isLoggedIn = true
let isAdmin = false
if isLoggedIn {
if isAdmin {
  print("Admin panel")
} else {
  print("Limited access")
}
  }

Use nested conditions to handle layered checks, such as authentication then role.

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Validate and Branch

Validate inputs first, then use a nested if to branch inside the valid case.

Example

let score = 85
if score >= 0 && score <= 100 {
  if score >= 90 {
print("A")
  } else if score >= 80 {
print("B")
  } else if score >= 70 {
print("C")
  } else {
print("Below C")
  }
} else {
  print("Invalid score")
}

Swift Short Hand If…Else

Use the ternary operator condition ? a : b for concise conditional expressions.

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Basic Ternary Operator

Use the ternary operator to choose between two values in a single expression.

Example

let age = 20
let status = (age >= 18) ? "Adult" : "Minor"
print(status)

This example returns “Adult” when age >= 18, otherwise “Minor”.

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REMOVE ADS

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Choose the Minimum

Use a ternary expression to select the smaller of two values.

Example

let a = 5, b = 9
let min = (a < b) ? a : b
print(min)

This prints the smaller number.

If a is not less than b, the expression returns b.

Swift else if

Chain multiple conditions with else if for more than two branches.

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Branch with else if conditions

Use else if for additional conditions when the first if is false.

Example

let score = 72
if score >= 90 {
  print("A")
} else if score >= 80 {
  print("B")
} else if score >= 70 {
  print("C")
} else {
  print("Below C")
}

This example evaluates multiple ranges using chained else if clauses.

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REMOVE ADS

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Temperature Levels

Use multiple else if branches to categorize values.

Example

let t = 0
if t <= 0 {
  print("Freezing")
} else if t < 10 {
  print("Cold")
} else if t < 20 {
  print("Cool")
} else {
  print("Warm")
}

Swift else

Use else to handle the false branch of a condition.

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Handle the false branch with else

Use else to run an alternate block when the condition is false.

Example

let hasAccess = false
if hasAccess {
  print("Welcome")
} else {
  print("Denied")
}

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Age Gate

Use else to handle when a user does not meet a requirement.

Example

let age = 16
if age >= 18 {
  print("Access granted")
} else {
  print("Access denied")
}

Swift if

Execute code conditionally when an expression evaluates to true.

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Basic if

Run code only when a condition evaluates to true.

Example

let temp = 25
if temp > 20 {
  print("Warm")
}

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Threshold Check

Trigger an action only when a value exceeds a threshold.

Example

let speed = 55
if speed > 50 {
  print("Slow down")
}

Swift If…Else

Control the flow of your program with if, else if, and else.

Combine conditions with logical operators.

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Basic If…Else

Use if to run code when a condition is true.

Add else for the false case, and else if for multiple branches.

Example

let score = 82
if score >= 90 {
  print("A")
} else if score >= 80 {
  print("B")
} else {
  print("C or lower")
}

This example prints a letter grade based on the score.

Tip: Swift conditions must be Bool.

There is no implicit conversion from integers to booleans.

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Even or Odd

Use else to handle the alternate outcome.

Example

let n = 7
if n % 2 == 0 {
  print("Even")
} else {
  print("Odd")
}

Swift Ranges

Use ranges to express a sequence of values.

a...b is a closed range including both ends.

a..<b is a half-open range up to but not including b.

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Closed and Half-Open

Use a...b for closed ranges (inclusive) and a..<b for half-open ranges (exclusive upper bound).

Example

for n in 1...5 {
  print(n)
} 
for n in 1..<5 {
  print(n)
}
let r = 10...12
print(r.contains(11))
print(r.contains(13))

This example iterates over closed and half-open ranges and checks membership with contains().

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One-Sided Ranges

One sided ranges omit one end: ...b starts from the beginning, and a... goes to the end.

Example

let arr = [0, 1, 2, 3, 4]
print(arr[...2])  // first three elements (indices 0...2)
print(arr[2...])  // from index 2 to the end

Swift Arrays: Real-Life Examples

Arrays are everywhere: rendering lists, aggregating values, finding items, and transforming data.

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Aggregate and Transform

Use filter, map, and reduce to process arrays declaratively.

Example

let scores = [72, 88, 95, 64, 83]
let passed = scores.filter { $0 >= 75 }
let curved = passed.map { $0 + 5 }
let average = curved.reduce(0, +) / curved.count
print(passed)
print(curved)
print("Average: \(average)")

Filter to keep passing scores, map to apply a curve, then reduce to compute an average.

Tip: Prefer declarative iteration for clarity and fewer bugs.

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Search & Index

Check for membership and find the index of a value.

Example

let names = ["Kai", "Bjorn", "Stale"]
print(names.contains("Bjorn"))            // true
if let i = names.firstIndex(of: "Stale") {
  print(i)                                 // 2
}