Remove collection-functions
Now that we have generics, this example is not relevant. Updates #349
This commit is contained in:
parent
3c2447b2d1
commit
881bb5d41c
@ -45,7 +45,6 @@ Sorting by Functions
|
||||
Panic
|
||||
Defer
|
||||
Recover
|
||||
Collection Functions
|
||||
String Functions
|
||||
String Formatting
|
||||
Text Templates
|
||||
|
@ -1,113 +0,0 @@
|
||||
// We often need our programs to perform operations on
|
||||
// collections of data, like selecting all items that
|
||||
// satisfy a given predicate or mapping all items to a new
|
||||
// collection with a custom function.
|
||||
|
||||
// In some languages it's idiomatic to use [generic](http://en.wikipedia.org/wiki/Generic_programming)
|
||||
// data structures and algorithms. Go does not support
|
||||
// generics; in Go it's common to provide collection
|
||||
// functions if and when they are specifically needed for
|
||||
// your program and data types.
|
||||
|
||||
// Here are some example collection functions for slices
|
||||
// of `strings`. You can use these examples to build your
|
||||
// own functions. Note that in some cases it may be
|
||||
// clearest to just inline the collection-manipulating
|
||||
// code directly, instead of creating and calling a
|
||||
// helper function.
|
||||
|
||||
package main
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"strings"
|
||||
)
|
||||
|
||||
// Index returns the first index of the target string `t`, or
|
||||
// -1 if no match is found.
|
||||
func Index(vs []string, t string) int {
|
||||
for i, v := range vs {
|
||||
if v == t {
|
||||
return i
|
||||
}
|
||||
}
|
||||
return -1
|
||||
}
|
||||
|
||||
// Include returns `true` if the target string t is in the
|
||||
// slice.
|
||||
func Include(vs []string, t string) bool {
|
||||
return Index(vs, t) >= 0
|
||||
}
|
||||
|
||||
// Any returns `true` if one of the strings in the slice
|
||||
// satisfies the predicate `f`.
|
||||
func Any(vs []string, f func(string) bool) bool {
|
||||
for _, v := range vs {
|
||||
if f(v) {
|
||||
return true
|
||||
}
|
||||
}
|
||||
return false
|
||||
}
|
||||
|
||||
// All returns `true` if all of the strings in the slice
|
||||
// satisfy the predicate `f`.
|
||||
func All(vs []string, f func(string) bool) bool {
|
||||
for _, v := range vs {
|
||||
if !f(v) {
|
||||
return false
|
||||
}
|
||||
}
|
||||
return true
|
||||
}
|
||||
|
||||
// Filter returns a new slice containing all strings in the
|
||||
// slice that satisfy the predicate `f`.
|
||||
func Filter(vs []string, f func(string) bool) []string {
|
||||
vsf := make([]string, 0)
|
||||
for _, v := range vs {
|
||||
if f(v) {
|
||||
vsf = append(vsf, v)
|
||||
}
|
||||
}
|
||||
return vsf
|
||||
}
|
||||
|
||||
// Map returns a new slice containing the results of applying
|
||||
// the function `f` to each string in the original slice.
|
||||
func Map(vs []string, f func(string) string) []string {
|
||||
vsm := make([]string, len(vs))
|
||||
for i, v := range vs {
|
||||
vsm[i] = f(v)
|
||||
}
|
||||
return vsm
|
||||
}
|
||||
|
||||
func main() {
|
||||
|
||||
// Here we try out our various collection functions.
|
||||
var strs = []string{"peach", "apple", "pear", "plum"}
|
||||
|
||||
fmt.Println(Index(strs, "pear"))
|
||||
|
||||
fmt.Println(Include(strs, "grape"))
|
||||
|
||||
fmt.Println(Any(strs, func(v string) bool {
|
||||
return strings.HasPrefix(v, "p")
|
||||
}))
|
||||
|
||||
fmt.Println(All(strs, func(v string) bool {
|
||||
return strings.HasPrefix(v, "p")
|
||||
}))
|
||||
|
||||
fmt.Println(Filter(strs, func(v string) bool {
|
||||
return strings.Contains(v, "e")
|
||||
}))
|
||||
|
||||
// The above examples all used anonymous functions,
|
||||
// but you can also use named functions of the correct
|
||||
// type.
|
||||
fmt.Println(Map(strs, strings.ToUpper))
|
||||
|
||||
}
|
@ -1,2 +0,0 @@
|
||||
002b2ee17f1111c7607a7b7742753af1b5a3c8c1
|
||||
uKnePZM91WV
|
@ -1,7 +0,0 @@
|
||||
$ go run collection-functions.go
|
||||
2
|
||||
false
|
||||
true
|
||||
false
|
||||
[peach apple pear]
|
||||
[PEACH APPLE PEAR PLUM]
|
2
public/index.html
generated
2
public/index.html
generated
@ -121,8 +121,6 @@
|
||||
|
||||
<li><a href="recover">Recover</a></li>
|
||||
|
||||
<li><a href="collection-functions">Collection Functions</a></li>
|
||||
|
||||
<li><a href="string-functions">String Functions</a></li>
|
||||
|
||||
<li><a href="string-formatting">String Formatting</a></li>
|
||||
|
4
public/recover
generated
4
public/recover
generated
@ -14,7 +14,7 @@
|
||||
|
||||
|
||||
if (e.key == "ArrowRight") {
|
||||
window.location.href = 'collection-functions';
|
||||
window.location.href = 'string-functions';
|
||||
}
|
||||
|
||||
}
|
||||
@ -180,7 +180,7 @@ panic and resumes in the deferred closure.</p>
|
||||
|
||||
|
||||
<p class="next">
|
||||
Next example: <a href="collection-functions">Collection Functions</a>.
|
||||
Next example: <a href="string-functions">String Functions</a>.
|
||||
</p>
|
||||
|
||||
|
||||
|
2
public/string-functions
generated
2
public/string-functions
generated
@ -9,7 +9,7 @@
|
||||
onkeydown = (e) => {
|
||||
|
||||
if (e.key == "ArrowLeft") {
|
||||
window.location.href = 'collection-functions';
|
||||
window.location.href = 'recover';
|
||||
}
|
||||
|
||||
|
||||
|
Loading…
x
Reference in New Issue
Block a user