1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
|
//===--- Reduce.swift - tests for the two reduce variants -----------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
// RUN: %target-run-simple-swift | %FileCheck %s
// REQUIRES: executable_test
// CHECK: testing...
print("testing...")
// Test the examples from the documentation of reduce(_:_:) and reduce(into:_:)
let numbers = [1, 2, 3, 4]
let numberSum = numbers.reduce(0, { x, y in
x + y
})
// CHECK-NEXT: 10
print("\(numberSum)")
let letters = "abracadabra"
let letterCount = letters.reduce(into: [:]) { counts, letter in
counts[letter, default: 0] += 1
}
// CHECK-NEXT: ["a", "b", "c", "d", "r"]
do {
var output = ""
var prefix = ""
for x in letterCount.keys.sorted() {
output += "\(prefix)\"\(x)\""
prefix = ", "
}
print("[\(output)]")
}
print("\(letterCount["a"]!)") // CHECK: 5
print("\(letterCount["b"]!)") // CHECK: 2
print("\(letterCount["c"]!)") // CHECK: 1
print("\(letterCount["d"]!)") // CHECK: 1
print("\(letterCount["r"]!)") // CHECK: 2
// Test the two reduce methods with different levels of inference
let numbers2 = Array(2..<7)
// Test reduce(_:_:)
// CHECK-NEXT: 20
let sum1 = numbers2.reduce(0) { (x: Int, y: Int) -> Int in x + y }
print("\(sum1)")
// CHECK-NEXT: 20
let sum2 = numbers2.reduce(0) { (x, y) in x + y }
print("\(sum2)")
// CHECK-NEXT: 20
let sum3 = numbers2.reduce(0) { $0 + $1 }
print("\(sum3)")
// CHECK-NEXT: 20
let sum4 = numbers2.reduce(0, +)
print("\(sum4)")
// Test reduce(into:_:)
// CHECK-NEXT: 20
let sum5 = numbers2.reduce(into: 0) { (x: inout Int, y: Int) in x += y }
print("\(sum5)")
// CHECK-NEXT: 20
let sum6 = numbers2.reduce(into: 0) { x, y in x += y }
print("\(sum6)")
// CHECK-NEXT: 20
let sum7 = numbers2.reduce(into: 0) { $0 += $1 }
print("\(sum7)")
// CHECK-NEXT: 20
let sum8 = numbers2.reduce(into: 0, +=)
print("\(sum8)")
// Test that the initial value remains unmodified
var original = [0, 1]
let result = numbers2.reduce(into: original) { acc, x in
acc.append(x)
}
// CHECK-NEXT: [0, 1]
do {
var output = ""
var prefix = ""
for x in original {
output += "\(prefix)\(x)"
prefix = ", "
}
print("[\(output)]")
}
// CHECK-NEXT: [0, 1, 2, 3, 4, 5, 6]
do {
var output = ""
var prefix = ""
for x in result {
output += "\(prefix)\(x)"
prefix = ", "
}
print("[\(output)]")
}
// CHECK: all done.
print("all done.")
|
