Merge pull request #1 from oze4/add-splice

Add Splice function
matthewoestreich · Aug 14, 2024 · 4761416 · 4761416
2 parents 2d1f356 + 5cdecc5
commit 4761416
Show file tree

Hide file tree

Showing 3 changed files with 270 additions and 4 deletions.
diff --git a/README.md b/README.md
@@ -166,6 +166,81 @@ r := jslice.Slice(s, start, end)
 // r == []int{1,2,3}
 ```
 
+## Splice
+
+Changes the contents of a slice by removing or replacing existing elements and/or adding new elements.
+
+- If `deleteCount` and `replacementElements` both equal `0`, we just return the original slice without modifying anything.
+- If `start` is greater than or equal to the length of the slice, no elements will be deleted, but the method will behave as an adding function.
+
+<b>Remove `0` elements before index `2` and insert "`earth`" and "`mars`"</b>
+```go
+s := []string{"mercury", "venus", "jupiter", "saturn"}
+jslice.Splice(&s, 2, 0, "earth", "mars")
+// s == []string{"mercury", "venus", "earth", "mars", "jupiter", "saturn"}
+```
+
+**Remove `0` elements at index `0` and insert "`earth`" and "`mars`".**
+
+```go
+s := []string{"mercury", "venus", "jupiter", "saturn"}
+jslice.Splice(&s, 0, 0, "earth", "mars")
+// s == []string{"earth", "mars", "mercury", "venus", "jupiter", "saturn"}
+```
+
+**Remove `1` element at index `2`, and insert "`earth`" and "`mars`"**
+
+```go
+s := []string{"mercury", "venus", "jupiter", "saturn"}
+jslice.Splice(&s, 2, 1, "earth", "mars")
+// s == []string{"mercury", "venus", "earth", "mars", "saturn"}
+```
+
+**Remove `1` element at index `0` and insert "`earth`" and "`mars`"**
+
+```go
+s := []string{"mercury", "venus", "jupiter", "saturn"}
+jslice.Splice(&s, 0, 1, "earth", "mars")
+// s == []string{"earth", "mars", "venus", "jupiter", "saturn"}
+```
+
+**Remove `3` elements starting at index `1` and insert nothing**
+
+```go
+s := []string{"mercury", "venus", "jupiter", "saturn"}
+jslice.Splice(&s, 1, 3)
+// s == []string{"mercury"}
+```
+
+**If `start` + `deleteCount` is greater than or equal to slice length, we modify `deleteCount` to equal the length of the slice - `start`**
+
+```go
+s := []string{"mercury", "venus", "jupiter", "saturn"}
+jslice.Splice(&s, 2, 100) // <- 100 greater than slice length
+// s == []string{"mercury", "venus"}
+```
+
+**If `start` is greater than or equal to the length of the slice, no elements are removed, but the method is treated as an add function**
+
+```go
+s := []string{"mercury", "venus", "jupiter", "saturn"}
+// Even though `deleteCount` == 1, nothing will be
+// deleted because `start` >= length of slice.
+jslice.Splice(&s, 100, 1, "earth", "mars") 
+// s == []string{"mercury", "venus", "jupiter", "saturn", "earth", "mars"}
+```
+
+**Splice last element by removing `1` element at index `3` and inserting "`earth`" and "`mars`"**
+
+```go
+s := []string{"mercury", "venus", "jupiter", "saturn"}
+jslice.Splice(&s, 3, 1, "earth", "mars")
+// s == []string{"mercury", "venus", "jupiter", "earth", "mars"}
+```
+
+
+
+
 <br />
 <br />
 <br />

diff --git a/jslice_test.go b/jslice_test.go
@@ -160,7 +160,7 @@ func TestEvery(t *testing.T) {
 
 func TestSlice(t *testing.T) {
 	const (
-		EXPECT_OG_LEN = 5
+		EXPECT_OG_LEN     = 5
 		EXPECT_SLICED_LEN = 3
 	)
 	s := []int{1, 2, 3, 4, 5}
@@ -177,21 +177,183 @@ func TestSlice(t *testing.T) {
 
 func TestShift(t *testing.T) {
 	const (
-		EXPECT_OG_LEN = 3
+		EXPECT_OG_LEN     = 3
 		EXPECT_RESULT_VAL = 1
 	)
-	s := []int{1,2,3,4}
+	s := []int{1, 2, 3, 4}
 	r := jslice.Shift(&s)
 	if len(s) != EXPECT_OG_LEN {
 		t.Fatalf("Expected original slice length to now be = %d | Got = %d\n", EXPECT_OG_LEN, len(s))
 	}
-	if (r != EXPECT_RESULT_VAL) {
+	if r != EXPECT_RESULT_VAL {
 		t.Fatalf("Expected result value to be = %d | Got = %d\n", EXPECT_RESULT_VAL, r)
 	}
 	t.Log(s)
 	t.Log(r)
 }
 
+func TestSplice_StartIndex2_Delete0_Insert2(t *testing.T) {
+	EXPECT := []string{"mercury", "venus", "earth", "mars", "jupiter", "saturn"}
+	s := []string{"mercury", "venus", "jupiter", "saturn"}
+
+	jslice.Splice(&s, 2, 0, "earth", "mars")
+
+	if len(EXPECT) != len(s) {
+		t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+	}
+	// use jslice to help with testing ;)
+	jslice.ForEach(s, func(i int, e string) {
+		if EXPECT[i] != e {
+			t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+		}
+	})
+	t.Log(s)
+}
+
+func TestSplice_StartIndex0_Delete0_Insert2(t *testing.T) {
+	EXPECT := []string{"earth", "mars", "mercury", "venus", "jupiter", "saturn"}
+	s := []string{"mercury", "venus", "jupiter", "saturn"}
+
+	jslice.Splice(&s, 0, 0, "earth", "mars")
+
+	if len(EXPECT) != len(s) {
+		t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+	}
+	// use jslice to help with testing ;)
+	jslice.ForEach(s, func(i int, e string) {
+		if EXPECT[i] != e {
+			t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+		}
+	})
+	t.Log(s)
+}
+
+func TestSplice_StartIndex2_Delete1_Insert2(t *testing.T) {
+	EXPECT := []string{"mercury", "venus", "earth", "mars", "saturn"}
+	s := []string{"mercury", "venus", "jupiter", "saturn"}
+
+	jslice.Splice(&s, 2, 1, "earth", "mars")
+
+	if len(EXPECT) != len(s) {
+		t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+	}
+	// use jslice to help with testing ;)
+	jslice.ForEach(s, func(i int, e string) {
+		if EXPECT[i] != e {
+			t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+		}
+	})
+	t.Log(s)
+}
+
+func TestSplice_StartIndex0_Delete1_Insert2(t *testing.T) {
+	EXPECT := []string{"earth", "mars", "venus", "jupiter", "saturn"}
+	s := []string{"mercury", "venus", "jupiter", "saturn"}
+
+	jslice.Splice(&s, 0, 1, "earth", "mars")
+
+	if len(EXPECT) != len(s) {
+		t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+	}
+	// use jslice to help with testing ;)
+	jslice.ForEach(s, func(i int, e string) {
+		if EXPECT[i] != e {
+			t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+		}
+	})
+	t.Log(s)
+}
+
+func TestSplice_StartIndex1_DeleteCount0_Insert0(t *testing.T) {
+	EXPECT := []string{"mercury"}
+	s := []string{"mercury", "venus", "jupiter", "saturn"}
+
+	jslice.Splice(&s, 1, 3)
+
+	if len(EXPECT) != len(s) {
+		t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+	}
+	// use jslice to help with testing ;)
+	jslice.ForEach(s, func(i int, e string) {
+		if EXPECT[i] != e {
+			t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+		}
+	})
+	t.Log(s)
+}
+
+func TestSplice_DeleteCountGreaterThanSliceLen(t *testing.T) {
+	EXPECT := []string{"mercury", "venus"}
+	s := []string{"mercury", "venus", "jupiter", "saturn"}
+
+	jslice.Splice(&s, 2, 100)
+
+	if len(EXPECT) != len(s) {
+		t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+	}
+	// use jslice to help with testing ;)
+	jslice.ForEach(s, func(i int, e string) {
+		if EXPECT[i] != e {
+			t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+		}
+	})
+	t.Log(s)
+}
+
+func TestSplice_StartIndexGreaterThanSliceLen_WithoutReplacementItems(t *testing.T) {
+	EXPECT := []string{"mercury", "venus", "jupiter", "saturn"}
+	s := []string{"mercury", "venus", "jupiter", "saturn"}
+
+	jslice.Splice(&s, 100, 100)
+
+	if len(EXPECT) != len(s) {
+		t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+	}
+	// use jslice to help with testing ;)
+	jslice.ForEach(s, func(i int, e string) {
+		if EXPECT[i] != e {
+			t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+		}
+	})
+	t.Log(s)
+}
+
+func TestSplice_StartIndexGreaterThanSliceLen_WithReplacementItems(t *testing.T) {
+	EXPECT := []string{"mercury", "venus", "jupiter", "saturn", "earth", "mars"}
+	s := []string{"mercury", "venus", "jupiter", "saturn"}
+
+	jslice.Splice(&s, 100, 1, "earth", "mars")
+
+	if len(EXPECT) != len(s) {
+		t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+	}
+	// use jslice to help with testing ;)
+	jslice.ForEach(s, func(i int, e string) {
+		if EXPECT[i] != e {
+			t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+		}
+	})
+	t.Log(s)
+}
+
+func TestSplice_SpliceLastElement(t *testing.T) {
+	EXPECT := []string{"mercury", "venus", "jupiter", "earth", "mars"}
+	s := []string{"mercury", "venus", "jupiter", "saturn"}
+
+	jslice.Splice(&s, 3, 1, "earth", "mars")
+
+	if len(EXPECT) != len(s) {
+		t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+	}
+	// use jslice to help with testing ;)
+	jslice.ForEach(s, func(i int, e string) {
+		if EXPECT[i] != e {
+			t.Fatalf("\nExpected\t= %v\nGot\t\t= %v\n", EXPECT, s)
+		}
+	})
+	t.Log(s)
+}
+
 // **************************************************************
 
 func TestTest(t *testing.T) {

diff --git a/splice.go b/splice.go
@@ -0,0 +1,29 @@
+package jslice
+
+// Splice changes the contents of a slice by removing or replacing existing elements,
+// and/or adding new elements.
+func Splice[T any](s *[]T, start uint, deleteCount uint, replacementItems ...T) {
+	if deleteCount == 0 && len(replacementItems) == 0 {
+		return //*s
+	}
+
+    // If start >= len(*s) no elements will be deleted, but the method will behave as
+    // an adding function.
+    if start >= uint(len(*s)) {
+        if len(replacementItems) == 0 {
+            return //*s
+        }
+        *s = append(*s, replacementItems...)
+        return //*s
+    }
+
+    // If the "end" (start+deleteCount) is greater than the length of the slice, limit
+    // the delete count to the length of the slice - start. Otherwise we get index out
+    // of bounds error.
+    if start + deleteCount >= uint(len(*s)) {
+        deleteCount = uint(len(*s)) - start
+    }
+
+	*s = append((*s)[0:start], append(replacementItems, (*s)[start+deleteCount:]...)...)
+	return //*s
+}