From cb0f486f012c9f176ede669fc5c3cc949da23b32 Mon Sep 17 00:00:00 2001
From: xlj <xlj@xulingjiaotekiMacBook-Pro.local>
Date: Thu, 14 Dec 2023 18:13:33 +0800
Subject: [PATCH 1/2] add doc for slices

---
 117-Slices/slices-0.gop  | 53 ----------------------------------------
 117-Slices/slices-01.gop | 18 ++++++++++++++
 117-Slices/slices-02.gop |  6 +++++
 117-Slices/slices-03.gop | 22 +++++++++++++++++
 117-Slices/slices-04.gop | 27 ++++++++++++++++++++
 117-Slices/slices-05.gop | 24 ++++++++++++++++++
 117-Slices/slices-06.gop | 27 ++++++++++++++++++++
 117-Slices/slices-07.gop |  9 +++++++
 117-Slices/slices-08.gop | 29 ++++++++++++++++++++++
 117-Slices/slices-09.gop | 23 +++++++++++++++++
 117-Slices/slices-1.gop  |  3 ---
 117-Slices/slices-10.gop | 27 ++++++++++++++++++++
 117-Slices/slices-11.gop | 10 ++++++++
 117-Slices/slices-12.gop | 17 +++++++++++++
 117-Slices/slices-2.gop  |  6 -----
 117-Slices/slices-3.gop  | 20 ---------------
 16 files changed, 239 insertions(+), 82 deletions(-)
 delete mode 100644 117-Slices/slices-0.gop
 create mode 100644 117-Slices/slices-01.gop
 create mode 100644 117-Slices/slices-02.gop
 create mode 100644 117-Slices/slices-03.gop
 create mode 100644 117-Slices/slices-04.gop
 create mode 100644 117-Slices/slices-05.gop
 create mode 100644 117-Slices/slices-06.gop
 create mode 100644 117-Slices/slices-07.gop
 create mode 100644 117-Slices/slices-08.gop
 create mode 100644 117-Slices/slices-09.gop
 delete mode 100644 117-Slices/slices-1.gop
 create mode 100644 117-Slices/slices-10.gop
 create mode 100644 117-Slices/slices-11.gop
 create mode 100644 117-Slices/slices-12.gop
 delete mode 100644 117-Slices/slices-2.gop
 delete mode 100644 117-Slices/slices-3.gop

diff --git a/117-Slices/slices-0.gop b/117-Slices/slices-0.gop
deleted file mode 100644
index 96fedbc..0000000
--- a/117-Slices/slices-0.gop
+++ /dev/null
@@ -1,53 +0,0 @@
-// _Slices_ are a key data type in Go+, giving a more
-// powerful interface to sequences than arrays.
-
-# Slice foundations
-
-// Unlike arrays, slices are typed only by the
-// elements they contain (not the number of elements).
-// To create an empty slice with non-zero length, use
-// the builtin `make`. Here we make a slice of
-// `string`s of length `3` (initially zero-valued).
-s := make([]string, 3)
-println "emp:", s
-
-// We can set and get just like with arrays.
-s[0] = "a"
-s[1] = "b"
-s[2] = "c"
-println "set:", s
-println "get:", s[2]
-
-// `len` returns the length of the slice as expected.
-println "len:", len(s)
-
-// In addition to these basic operations, slices
-// support several more that make them richer than
-// arrays. One is the builtin `append`, which
-// returns a slice containing one or more new values.
-// Note that we need to accept a return value from
-// `append` as we may get a new slice value.
-s = append(s, "d")
-s = append(s, "e", "f")
-println "apd:", s
-
-// Slices can also be `copy`'d. Here we create an
-// empty slice `c` of the same length as `s` and copy
-// into `c` from `s`.
-c := make([]string, len(s))
-copy c, s
-println "cpy:", c
-
-// Slices support a "slice" operator with the syntax
-// `slice[low:high]`. For example, this gets a slice
-// of the elements `s[2]`, `s[3]`, and `s[4]`.
-l := s[2:5]
-println "sl1:", l
-
-// This slices up to (but excluding) `s[5]`.
-l = s[:5]
-println "sl2:", l
-
-// And this slices up from (and including) `s[2]`.
-l = s[2:]
-println "sl3:", l
diff --git a/117-Slices/slices-01.gop b/117-Slices/slices-01.gop
new file mode 100644
index 0000000..a945f8c
--- /dev/null
+++ b/117-Slices/slices-01.gop
@@ -0,0 +1,18 @@
+# Slice literals in Go+ style
+// A slice is a collection of data elements of the same type. A slice literal is a list of expressions surrounded by square brackets. An individual element can be accessed using an index expression. Indexes start from 0.
+//
+// In go+, you can get slice length directly from len method, and you can casting slice literals:
+
+f64 := []float64([1, 2, 3]) // []float64
+println(f64, f64.len)       // get length by len method
+
+nums := [1, 2, 3]
+println nums      // [1 2 3]
+println nums.len  // 3, go+ support
+println nums[0]   // 1
+println nums[1:3] // [2 3]
+println nums[:2]  // [1 2]
+println nums[2:]  // [3]
+
+nums[1] = 5
+println nums // [1 5 3]
\ No newline at end of file
diff --git a/117-Slices/slices-02.gop b/117-Slices/slices-02.gop
new file mode 100644
index 0000000..1ce2019
--- /dev/null
+++ b/117-Slices/slices-02.gop
@@ -0,0 +1,6 @@
+# Slice
+// An array has a fixed size. A slice, on the other hand, is a dynamically-sized, flexible view into the elements of an array. In practice, slices are much more common than arrays.
+//
+// The type []T is a slice with elements of type T.
+//
+// A slice is formed by specifying two indices, a low and high bound, separated by a colon: a[low : high]. This selects a half-open range which includes the first element, but excludes the last one.
diff --git a/117-Slices/slices-03.gop b/117-Slices/slices-03.gop
new file mode 100644
index 0000000..6d498ee
--- /dev/null
+++ b/117-Slices/slices-03.gop
@@ -0,0 +1,22 @@
+# Slices are like references to arrays
+// A slice does not store any data, it just describes a section of an underlying array.
+//
+// Changing the elements of a slice modifies the corresponding elements of its underlying array.
+//
+// Other slices that share the same underlying array will see those changes.
+
+names := [4]string{
+	"John",
+	"Paul",
+	"George",
+	"Ringo",
+}
+println names
+
+a := names[0:2]
+b := names[1:3]
+println a, b
+
+b[0] = "XXX"
+println a, b
+println names
diff --git a/117-Slices/slices-04.gop b/117-Slices/slices-04.gop
new file mode 100644
index 0000000..046a5ae
--- /dev/null
+++ b/117-Slices/slices-04.gop
@@ -0,0 +1,27 @@
+# Slice literals
+// A slice literal is like an array literal without the length.
+// <pre>
+// This is an array literal:
+// [3]bool{true, true, false}
+// And this creates the same array as above, then builds a slice that references it:
+// []bool{true, true, false}
+// </pre>
+
+q := []int{2, 3, 5, 7, 11, 13}
+println q
+
+r := []bool{true, false, true, true, false, true}
+println r
+
+s := []struct {
+	i int
+	b bool
+}{
+	{2, true},
+	{3, false},
+	{5, true},
+	{7, true},
+	{11, false},
+	{13, true},
+}
+println s
diff --git a/117-Slices/slices-05.gop b/117-Slices/slices-05.gop
new file mode 100644
index 0000000..dd4e4e2
--- /dev/null
+++ b/117-Slices/slices-05.gop
@@ -0,0 +1,24 @@
+# Slice defaults
+// When slicing, you may omit the high or low bounds to use their defaults instead.
+// 
+// The default is zero for the low bound and the length of the slice for the high bound.
+// <pre>
+// For the array
+// var a [10]int
+// these slice expressions are equivalent:
+// a[0:10]
+// a[:10]
+// a[0:]
+// a[:]
+// </pre>
+
+s := []int{2, 3, 5, 7, 11, 13}
+
+s = s[1:4]
+println s
+
+s = s[:2]
+println s
+
+s = s[1:]
+println s
\ No newline at end of file
diff --git a/117-Slices/slices-06.gop b/117-Slices/slices-06.gop
new file mode 100644
index 0000000..b77b3e5
--- /dev/null
+++ b/117-Slices/slices-06.gop
@@ -0,0 +1,27 @@
+# Slice length and capacity
+// A slice has both a length and a capacity.
+//
+// The length of a slice is the number of elements it contains.
+//
+// The capacity of a slice is the number of elements in the underlying array, counting from the first element in the slice.
+//
+// The length and capacity of a slice s can be obtained using the expressions len(s) and cap(s).
+//
+// You can extend a slice's length by re-slicing it, provided it has sufficient capacity. Try changing one of the slice operations in the example program to extend it beyond its capacity and see what happens.
+
+func printSlice(s []int) {
+	printf "len=%d cap=%d %v\n", len(s), cap(s), s
+}
+
+s := []int{2, 3, 5, 7, 11, 13}
+printSlice s
+
+
+s = s[:0] // Slice the slice to give it zero length.
+printSlice s
+
+s = s[:4] // Extend its length.
+printSlice s
+
+s = s[2:] // Drop its first two values.
+printSlice s
diff --git a/117-Slices/slices-07.gop b/117-Slices/slices-07.gop
new file mode 100644
index 0000000..605eb93
--- /dev/null
+++ b/117-Slices/slices-07.gop
@@ -0,0 +1,9 @@
+# Nil slices
+// The zero value of a slice is nil.
+// A nil slice has a length and capacity of 0 and has no underlying array.
+
+var s []int
+println s, len(s), cap(s)
+if s == nil {
+	println "nil!"
+}
\ No newline at end of file
diff --git a/117-Slices/slices-08.gop b/117-Slices/slices-08.gop
new file mode 100644
index 0000000..60fe2ca
--- /dev/null
+++ b/117-Slices/slices-08.gop
@@ -0,0 +1,29 @@
+# Creating a slice with make
+// Slices can be created with the built-in make function; this is how you create dynamically-sized arrays.
+//
+// The make function allocates a zeroed array and returns a slice that refers to that array:
+//
+//<pre>
+//a := make([]int, 5)			// len(a)=5
+//To specify a capacity, pass a third argument to make:
+//b := make([]int, 0, 5) 		// len(b)=0, cap(b)=5
+//b = b[:cap(b)] 				// len(b)=5, cap(b)=5
+//b = b[1:]      				// len(b)=4, cap(b)=4
+//</pre>
+
+func printSlice(s string, x []int) {
+	printf "%s len=%d cap=%d %v\n",
+		s, len(x), cap(x), x
+}
+
+a := make([]int, 5)
+printSlice "a", a
+
+b := make([]int, 0, 5)
+printSlice "b", b
+
+c := b[:2]
+printSlice "c", c
+
+d := c[2:5]
+printSlice "d", d
\ No newline at end of file
diff --git a/117-Slices/slices-09.gop b/117-Slices/slices-09.gop
new file mode 100644
index 0000000..4841ce9
--- /dev/null
+++ b/117-Slices/slices-09.gop
@@ -0,0 +1,23 @@
+# Slices of slices
+// Slices can contain any type, including other slices.
+// Create a tic-tac-toe board.
+
+import (
+	"strings"
+)
+
+board := [][]string{
+	[]string{"_", "_", "_"},
+	[]string{"_", "_", "_"},
+	[]string{"_", "_", "_"},
+}
+
+board[0][0] = "X" // The players take turns.
+board[2][2] = "O"
+board[1][2] = "X"
+board[1][0] = "O"
+board[0][2] = "X"
+
+for i := 0; i < len(board); i++ {
+	printf "%s\n", strings.join(board[i], " ")
+}
diff --git a/117-Slices/slices-1.gop b/117-Slices/slices-1.gop
deleted file mode 100644
index 619e07b..0000000
--- a/117-Slices/slices-1.gop
+++ /dev/null
@@ -1,3 +0,0 @@
-# Slice literals in Go+ style
-
-## TODO
diff --git a/117-Slices/slices-10.gop b/117-Slices/slices-10.gop
new file mode 100644
index 0000000..0e6acb3
--- /dev/null
+++ b/117-Slices/slices-10.gop
@@ -0,0 +1,27 @@
+# Appending to a slice
+// It is common to append new elements to a slice, and so Go provides a built-in append function. The documentation of the built-in package describes append.
+// 
+// func append(s []T, vs ...T) []T
+//
+// The first parameter s of append is a slice of type T, and the rest are T values to append to the slice.
+//
+// The resulting value of append is a slice containing all the elements of the original slice plus the provided values.
+//
+// If the backing array of s is too small to fit all the given values a bigger array will be allocated. The returned slice will point to the newly allocated array.
+
+func printSlice(s []int) {
+	printf "len=%d cap=%d %v\n", len(s), cap(s), s
+}
+
+var s []int
+
+printSlice s
+
+s = append(s, 0) // append works on nil slices.
+printSlice s
+
+s = append(s, 1) // The slice grows as needed.
+printSlice s
+
+s = append(s, 2, 3, 4) // We can add more than one element at a time.
+printSlice s
\ No newline at end of file
diff --git a/117-Slices/slices-11.gop b/117-Slices/slices-11.gop
new file mode 100644
index 0000000..a81116a
--- /dev/null
+++ b/117-Slices/slices-11.gop
@@ -0,0 +1,10 @@
+# Range
+// The range form of the for loop iterates over a slice or map.
+//
+// When ranging over a slice, two values are returned for each iteration. The first is the index, and the second is a copy of the element at that index.
+
+var pow = []int{1, 2, 4, 8, 16, 32, 64, 128}
+
+for i, v := range pow {
+	printf "2**%d = %d\n", i, v
+}
diff --git a/117-Slices/slices-12.gop b/117-Slices/slices-12.gop
new file mode 100644
index 0000000..968e43f
--- /dev/null
+++ b/117-Slices/slices-12.gop
@@ -0,0 +1,17 @@
+# Range continued
+//
+// <pre>
+// You can skip the index or value by assigning to _.
+// for i, _ := range pow
+// for _, value := range pow
+// If you only want the index, you can omit the second variable.
+// for i := range pow
+// </pre>
+
+pow := make([]int, 10)
+for i := range pow {
+	pow[i] = 1 << uint(i) // == 2**i
+}
+for _, value := range pow {
+	printf "%d\n", value
+}
diff --git a/117-Slices/slices-2.gop b/117-Slices/slices-2.gop
deleted file mode 100644
index a5b1abd..0000000
--- a/117-Slices/slices-2.gop
+++ /dev/null
@@ -1,6 +0,0 @@
-# Slice literals in Go style
-
-// We can declare and initialize a variable for slice
-// in a single line as well.
-t := []string{"g", "h", "i"}
-println "dcl:", t
diff --git a/117-Slices/slices-3.gop b/117-Slices/slices-3.gop
deleted file mode 100644
index dfc0090..0000000
--- a/117-Slices/slices-3.gop
+++ /dev/null
@@ -1,20 +0,0 @@
-# Slice advance
-
-buf := make([]byte, 0, 128)
-buf = append(buf, 'H', 'e', 'l', 'l', 'o')
-buf = append(buf, ' ')
-buf = append(buf, "world"...)
-println string(buf)
-
-// Slices can be composed into multi-dimensional data
-// structures. The length of the inner slices can
-// vary, unlike with multi-dimensional arrays.
-twoD := make([][]int, 3)
-for i := 0; i < 3; i++ {
-	innerLen := i + 1
-	twoD[i] = make([]int, innerLen)
-	for j := 0; j < innerLen; j++ {
-		twoD[i][j] = i + j
-	}
-}
-println "2d: ", twoD

From f9a2dcd84d6b69b967931acc2e9500105da4e1b6 Mon Sep 17 00:00:00 2001
From: xlj <xlj@xulingjiaotekiMacBook-Pro.local>
Date: Thu, 14 Dec 2023 19:22:12 +0800
Subject: [PATCH 2/2] fix fmt error

---
 117-Slices/slices-01.gop |  2 +-
 117-Slices/slices-05.gop | 13 ++++++-------
 117-Slices/slices-06.gop |  1 -
 117-Slices/slices-07.gop |  5 ++++-
 117-Slices/slices-08.gop |  2 +-
 117-Slices/slices-10.gop |  6 +++---
 6 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/117-Slices/slices-01.gop b/117-Slices/slices-01.gop
index a945f8c..cfedcbb 100644
--- a/117-Slices/slices-01.gop
+++ b/117-Slices/slices-01.gop
@@ -15,4 +15,4 @@ println nums[:2]  // [1 2]
 println nums[2:]  // [3]
 
 nums[1] = 5
-println nums // [1 5 3]
\ No newline at end of file
+println nums // [1 5 3]
diff --git a/117-Slices/slices-05.gop b/117-Slices/slices-05.gop
index dd4e4e2..6429fbd 100644
--- a/117-Slices/slices-05.gop
+++ b/117-Slices/slices-05.gop
@@ -1,8 +1,8 @@
 # Slice defaults
 // When slicing, you may omit the high or low bounds to use their defaults instead.
-// 
+//
 // The default is zero for the low bound and the length of the slice for the high bound.
-// <pre>
+//<pre>
 // For the array
 // var a [10]int
 // these slice expressions are equivalent:
@@ -10,15 +10,14 @@
 // a[:10]
 // a[0:]
 // a[:]
-// </pre>
-
+//</pre>
 s := []int{2, 3, 5, 7, 11, 13}
 
+s = s[1:]
+println s
+
 s = s[1:4]
 println s
 
 s = s[:2]
 println s
-
-s = s[1:]
-println s
\ No newline at end of file
diff --git a/117-Slices/slices-06.gop b/117-Slices/slices-06.gop
index b77b3e5..215d214 100644
--- a/117-Slices/slices-06.gop
+++ b/117-Slices/slices-06.gop
@@ -16,7 +16,6 @@ func printSlice(s []int) {
 s := []int{2, 3, 5, 7, 11, 13}
 printSlice s
 
-
 s = s[:0] // Slice the slice to give it zero length.
 printSlice s
 
diff --git a/117-Slices/slices-07.gop b/117-Slices/slices-07.gop
index 605eb93..286143a 100644
--- a/117-Slices/slices-07.gop
+++ b/117-Slices/slices-07.gop
@@ -1,9 +1,12 @@
 # Nil slices
 // The zero value of a slice is nil.
+//
 // A nil slice has a length and capacity of 0 and has no underlying array.
 
 var s []int
+
 println s, len(s), cap(s)
+
 if s == nil {
 	println "nil!"
-}
\ No newline at end of file
+}
diff --git a/117-Slices/slices-08.gop b/117-Slices/slices-08.gop
index 60fe2ca..d293e4d 100644
--- a/117-Slices/slices-08.gop
+++ b/117-Slices/slices-08.gop
@@ -26,4 +26,4 @@ c := b[:2]
 printSlice "c", c
 
 d := c[2:5]
-printSlice "d", d
\ No newline at end of file
+printSlice "d", d
diff --git a/117-Slices/slices-10.gop b/117-Slices/slices-10.gop
index 0e6acb3..8566772 100644
--- a/117-Slices/slices-10.gop
+++ b/117-Slices/slices-10.gop
@@ -1,6 +1,6 @@
 # Appending to a slice
 // It is common to append new elements to a slice, and so Go provides a built-in append function. The documentation of the built-in package describes append.
-// 
+//
 // func append(s []T, vs ...T) []T
 //
 // The first parameter s of append is a slice of type T, and the rest are T values to append to the slice.
@@ -10,7 +10,7 @@
 // If the backing array of s is too small to fit all the given values a bigger array will be allocated. The returned slice will point to the newly allocated array.
 
 func printSlice(s []int) {
-	printf "len=%d cap=%d %v\n", len(s), cap(s), s
+	printf "len = %d cap = %d %v\n", len(s), cap(s), s
 }
 
 var s []int
@@ -24,4 +24,4 @@ s = append(s, 1) // The slice grows as needed.
 printSlice s
 
 s = append(s, 2, 3, 4) // We can add more than one element at a time.
-printSlice s
\ No newline at end of file
+printSlice s