Javascript 是否可以以某种方式缩短switch语句?也许是打个圈?
独立于哪种编程语言,有哪些选项可以缩短具有许多类似情况的长switch语句 通过搜索,我找到了如下答案,但我的情况都不同,只有一个整数在循环中变化 我经常在bash/PHP/Python/JavaScript中使用以下switch语句构造,我正在寻找一个较短的版本:Javascript 是否可以以某种方式缩短switch语句?也许是打个圈?,javascript,php,python,bash,switch-statement,Javascript,Php,Python,Bash,Switch Statement,独立于哪种编程语言,有哪些选项可以缩短具有许多类似情况的长switch语句 通过搜索,我找到了如下答案,但我的情况都不同,只有一个整数在循环中变化 我经常在bash/PHP/Python/JavaScript中使用以下switch语句构造,我正在寻找一个较短的版本: switch ($device) { // 2ghz case "n2": return 1; break; case "nne2": return 2;
switch ($device) {
// 2ghz
case "n2":
return 1;
break;
case "nne2":
return 2;
break;
case "ne2":
return 3;
break;
case "ene2":
return 4;
break;
case "e2":
return 5;
break;
case "ese2":
return 6;
break;
case "se2":
return 7;
break;
case "sse2":
return 8;
break;
case "s2":
return 9;
break;
case "ssw2":
return 10;
break;
case "sw2":
return 11;
break;
case "wsw2":
return 12;
break;
case "w2":
return 13;
break;
case "wnw2":
return 14;
break;
case "nw2":
return 15;
break;
case "nnw2":
return 16;
break;
// 5ghz
case "n5":
return 17;
break;
case "nne5":
return 18;
break;
case "ne5":
return 19;
break;
case "ene5":
return 20;
break;
case "e5":
return 21;
break;
case "ese5":
return 22;
break;
case "se5":
return 23;
break;
case "sse5":
return 24;
break;
case "s5":
return 25;
break;
case "ssw5":
return 26;
break;
case "sw5":
return 27;
break;
case "wsw5":
return 28;
break;
case "w5":
return 29;
break;
case "wnw5":
return 30;
break;
case "nw5":
return 31;
break;
case "nnw5":
return 32;
break;
// 24ghz
case "n24":
return 33;
break;
case "nne24":
return 34;
break;
case "ne24":
return 35;
break;
case "ene24":
return 36;
break;
case "e24":
return 37;
break;
case "ese24":
return 38;
break;
case "se24":
return 39;
break;
case "sse24":
return 40;
break;
case "s24":
return 41;
break;
case "ssw24":
return 42;
break;
case "sw24":
return 43;
break;
case "wsw24":
return 44;
break;
case "w24":
return 45;
break;
case "wnw24":
return 46;
break;
case "nw24":
return 47;
break;
case "nnw24":
return 48;
break;
default:
return 0;
break;
}
使用数组将“cases”存储为键,并将值返回为值。
然后可以检查数组中是否存在给定的密钥。如果是,则返回其值,如果不是,则返回默认值 使用数组将“cases”存储为键,并将值返回为值。
然后可以检查数组中是否存在给定的密钥。如果是,则返回其值,如果不是,则返回默认值 我不懂php,所以这是用python编写的:
devices = ["n2", "nne2" ...] # populate it with your devices
...
def foo(device):
if device in devices:
return devices.index(device) + 1
else:
return 0
我不懂php,所以这是在python中:
devices = ["n2", "nne2" ...] # populate it with your devices
...
def foo(device):
if device in devices:
return devices.index(device) + 1
else:
return 0
如果号码是订购的。没有比使用数组索引更好的方法了 另一方面,如果值不同,则可以使用字典/哈希映射/关联数组的简单实现来完成解决方案 在Python中,可以使用字典,如下所示
keyList = ['n2','nne2',...]
valueList = [1, 2, 3, ...] # Must be same size as keyList
# Best to assign both the above lists
# with files if there are 50+ entries
deviceDict = {}
for i in range(len(keyList)):
deviceDict[keyList[i]] = valueList[i]
如果号码是订购的。没有比使用数组索引更好的方法了 另一方面,如果值不同,则可以使用字典/哈希映射/关联数组的简单实现来完成解决方案 在Python中,可以使用字典,如下所示
keyList = ['n2','nne2',...]
valueList = [1, 2, 3, ...] # Must be same size as keyList
# Best to assign both the above lists
# with files if there are 50+ entries
deviceDict = {}
for i in range(len(keyList)):
deviceDict[keyList[i]] = valueList[i]
用PHP试试这个
function yourFunction($devices) {
$array = ["n2","nne2","ne2","ene2","e2","ese2","se2","sse2","s2","ssw2","sw2","wsw2"];
if($key = array_search($devices, $array))
return $key+1;
}
用PHP试试这个
function yourFunction($devices) {
$array = ["n2","nne2","ne2","ene2","e2","ese2","se2","sse2","s2","ssw2","sw2","wsw2"];
if($key = array_search($devices, $array))
return $key+1;
}
在JavaScript中:
var cases = {
"n2" : 1,
"nne2" : 2,
"ne2" : 3,
"ene2" : 4,
"e2" : 5,
"ese2" : 6,
// and so on
};
var myCase = cases[$device] || 0;
在JavaScript中:
var cases = {
"n2" : 1,
"nne2" : 2,
"ne2" : 3,
"ene2" : 4,
"e2" : 5,
"ese2" : 6,
// and so on
};
var myCase = cases[$device] || 0;
在Python中,如果返回值如此简单,则可以使用如下简单的内容:
items = ["n2","nne2","ne2","ene2", ...]
for idx, key in enumerate(items, start=1):
if device == key:
result = idx
result = 0
或者,如果您期望返回值中有更复杂的内容:
my_dict = {
"n2": 1,
"nne2": 2,
"ne2": 3,
"ene2": 4,
...}
for key, value in my_dict.items():
if device == key:
result = value
result = 0
在Python中,如果返回值如此简单,则可以使用如下简单的内容:
items = ["n2","nne2","ne2","ene2", ...]
for idx, key in enumerate(items, start=1):
if device == key:
result = idx
result = 0
或者,如果您期望返回值中有更复杂的内容:
my_dict = {
"n2": 1,
"nne2": 2,
"ne2": 3,
"ene2": 4,
...}
for key, value in my_dict.items():
if device == key:
result = value
result = 0
我建议在bash中使用索引数组:
declare -A a=([n2]='1' [nne2]='2' [ne2]='3')
device="nne2"
return "${a[$device]}" # returns with value 2
我建议在bash中使用索引数组:
declare -A a=([n2]='1' [nne2]='2' [ne2]='3')
device="nne2"
return "${a[$device]}" # returns with value 2
如果您需要一个独立于任何特定编程语言的解决方案,您可以尝试JSON(Javascript对象表示法) 尽管名称不同,JSON是一种与语言无关、基于文本的数据交换格式,与XML、CSV(或YAML)非常相似 由于与语言无关,JSON不仅可以通过Javascript进行查询和处理,还可以通过Java、Python、PHP和许多其他语言进行查询和处理 多种语言可以引用和处理相同的JSON数据 问题中数据的JSON示例:
{
"2ghz": {
"n2": 1,
"nne2": 2,
"ne2": 3,
"ene2": 4,
"e2": 5,
"ese2": 6,
"se2": 7,
"sse2": 8,
"s2": 9,
"ssw2": 10,
"sw2": 11,
"wsw2": 12,
"w2": 13,
"wnw2": 14,
"nw2": 15,
"nnw2": 16
},
"5ghz": {
"n5": 17,
"nne5": 18,
"ne5": 19,
"ene5": 20,
"e5": 21,
"ese5": 22,
"se5": 23,
"sse5": 24,
"s5": 25,
"ssw5": 26,
"sw5": 27,
"wsw5": 28,
"w5": 29,
"wnw5": 30,
"nw5": 31,
"nnw5": 32,
},
"24ghz": {
"n24": 33,
"nne24": 34,
"ne24": 35,
"ene24": 36,
"e24": 37,
"ese24": 38,
"se24": 39,
"sse24": 40,
"s24": 41,
"ssw24": 42,
"sw24": 43,
"wsw24": 44,
"w24": 45,
"wnw24": 46,
"nw24": 47,
"nnw24": 48
}
}
如果您需要一个独立于任何特定编程语言的解决方案,您可以尝试JSON(Javascript对象表示法) 尽管名称不同,JSON是一种与语言无关、基于文本的数据交换格式,与XML、CSV(或YAML)非常相似 由于与语言无关,JSON不仅可以通过Javascript进行查询和处理,还可以通过Java、Python、PHP和许多其他语言进行查询和处理 多种语言可以引用和处理相同的JSON数据 问题中数据的JSON示例:
{
"2ghz": {
"n2": 1,
"nne2": 2,
"ne2": 3,
"ene2": 4,
"e2": 5,
"ese2": 6,
"se2": 7,
"sse2": 8,
"s2": 9,
"ssw2": 10,
"sw2": 11,
"wsw2": 12,
"w2": 13,
"wnw2": 14,
"nw2": 15,
"nnw2": 16
},
"5ghz": {
"n5": 17,
"nne5": 18,
"ne5": 19,
"ene5": 20,
"e5": 21,
"ese5": 22,
"se5": 23,
"sse5": 24,
"s5": 25,
"ssw5": 26,
"sw5": 27,
"wsw5": 28,
"w5": 29,
"wnw5": 30,
"nw5": 31,
"nnw5": 32,
},
"24ghz": {
"n24": 33,
"nne24": 34,
"ne24": 35,
"ene24": 36,
"e24": 37,
"ese24": 38,
"se24": 39,
"sse24": 40,
"s24": 41,
"ssw24": 42,
"sw24": 43,
"wsw24": 44,
"w24": 45,
"wnw24": 46,
"nw24": 47,
"nnw24": 48
}
}
非常感谢您的贡献,我可以举出以下例子。我希望它们是他们语言的最短变体,如果不是,请随意编辑/更正 Python dev2host.py:
#!/usr/bin/env python
def dev2host(device):
devices = [
"n2", "nne2", "ne2", "ene2", "e2", "ese2", "se2", "sse2", "s2", "ssw2", "sw2", "wsw2", "w2", "wnw2", "nw2", "nnw2", # 2ghz
"n5", "nne5", "ne5", "ene5", "e5", "ese5", "se5", "sse5", "s5", "ssw5", "sw5", "wsw5", "w5", "wnw5", "nw5", "nnw5", # 5ghz
"n24", "nne24", "ne24", "ene24", "e24", "ese24", "se24", "sse24", "s24", "ssw24", "sw24", "wsw24", "w24", "wnw24", "nw24", "nnw24", # 24ghz
]
for host, key in enumerate(devices, start=1):
if device == key:
print host
result = 0
return;
dev2host("ne5")
PHP dev2host.PHP:
<?php
function dev2host($device) {
$devices = [
"n2", "nne2", "ne2", "ene2", "e2", "ese2", "se2", "sse2", "s2", "ssw2", "sw2", "wsw2", "w2", "wnw2", "nw2", "nnw2", // 2ghz
"n5", "nne5", "ne5", "ene5", "e5", "ese5", "se5", "sse5", "s5", "ssw5", "sw5", "wsw5", "w5", "wnw5", "nw5", "nnw5", // 5ghz
"n24", "nne24", "ne24", "ene24", "e24", "ese24", "se24", "sse24", "s24", "ssw24", "sw24", "wsw24", "w24", "wnw24", "nw24", "nnw24", // 24ghz
];
if ($host = array_search($device, $devices)) {
return $host+1;
}
}
echo dev2host("ne5");
?>
Javascript dev2host.js:
函数dev2host($device){
var设备={
“n2”:1,“nne2”:2,“ne2”:3,“ene2”:4,“e2”:5,“ese2”:6,“se2”:7,“sse2”:8,//2ghz
“s2”:9,“ssw2”:10,“sw2”:11,“wsw2”:12,“w2”:13,“WW2”:14,“nw2”:15,“nnw2”:16,//2ghz
“n5”:17,“nnw5”:18,“ne5”:19,“ene5”:20,“e5”:21,“ese5”:22,“se5”:23,“sse5”:24,//5ghz
“s5”:25,“ssw5”:26,“sw5”:27,“wsw5”:28,“w5”:29,“WW5”:30,“nw5”:31,“nnw5”:32,//5ghz
“n24”:33,“nnw34”:34,“ne24”:35,“ene24”:36,“e24”:37,“ese24”:38,“se24”:39,“sse24”:40,//24ghz
“s24”:41,“ssw24”:42,“sw24”:43,“wsw24”:44,“w24”:45,“WW24”:46,“nw24”:47,“nnw24”:48,//24ghz
};
var host=devices[$device]| | 0;
返回主机;
}
编写(dev2host(“ne5”)代码>非常感谢您的贡献,我可以给出以下示例。我希望它们是他们语言的最短变体,如果不是,请随意编辑/更正
Python dev2host.py:
#!/usr/bin/env python
def dev2host(device):
devices = [
"n2", "nne2", "ne2", "ene2", "e2", "ese2", "se2", "sse2", "s2", "ssw2", "sw2", "wsw2", "w2", "wnw2", "nw2", "nnw2", # 2ghz
"n5", "nne5", "ne5", "ene5", "e5", "ese5", "se5", "sse5", "s5", "ssw5", "sw5", "wsw5", "w5", "wnw5", "nw5", "nnw5", # 5ghz
"n24", "nne24", "ne24", "ene24", "e24", "ese24", "se24", "sse24", "s24", "ssw24", "sw24", "wsw24", "w24", "wnw24", "nw24", "nnw24", # 24ghz
]
for host, key in enumerate(devices, start=1):
if device == key:
print host
result = 0
return;
dev2host("ne5")
PHP dev2host.PHP:
<?php
function dev2host($device) {
$devices = [
"n2", "nne2", "ne2", "ene2", "e2", "ese2", "se2", "sse2", "s2", "ssw2", "sw2", "wsw2", "w2", "wnw2", "nw2", "nnw2", // 2ghz
"n5", "nne5", "ne5", "ene5", "e5", "ese5", "se5", "sse5", "s5", "ssw5", "sw5", "wsw5", "w5", "wnw5", "nw5", "nnw5", // 5ghz
"n24", "nne24", "ne24", "ene24", "e24", "ese24", "se24", "sse24", "s24", "ssw24", "sw24", "wsw24", "w24", "wnw24", "nw24", "nnw24", // 24ghz
];
if ($host = array_search($device, $devices)) {
return $host+1;
}
}
echo dev2host("ne5");
?>
Javascript dev2host.js:
函数dev2host($device){
var设备={
“n2”:1,“nne2”:2,“ne2”:3,“ene2”:4,“e2”:5,“ese2”:6,“se2”:7,“sse2”:8,//2ghz
“s2”:9,“ssw2”:10,“sw2”:11,“wsw2”:12,“w2”:13,“WW2”:14,“nw2”:15,“nnw2”:16,//2ghz
“n5”:17,“nnw5”:18,“ne5”:19,“ene5”:20,“e5”:21,“ese5”:22,“se5”:23,“sse5”:24,//5ghz
“s5”:25,“ssw5”:26,“sw5”:27,“wsw5”:28,“w5”:29,“WW5”:30,“nw5”:31,“nnw5”:32,//5ghz
“n24”:33,“nnw34”:34,“ne24”:35,“ene24”:36,“e24”:37,“ese24”:38,“se24”:39,“sse24”:40,//24ghz
“s24”:41,“ssw24”:42,“sw24”:43,“wsw24”:44,“w24”:45,“WW24”:46,“nw24”:47,“nnw24”:48,//24ghz
};
var host=devices[$device]| | 0;
返回主机;
}
编写(dev2host(“ne5”)
如果每个开关案例都返回一个值,则可以从每个案例中删除break
。如果您只是返回一个值,则字典或hashmap更适合。一种包含键和值的数据类型,您在其中提供键并将值返回给您。您刚才是说在Python中使用switch语句吗?在这种情况下不需要switch,它可以很容易地使用数组来完成。我认为没有最好的方法可以在所有语言中涵盖这种情况。例如,在python中,您更喜欢if/else
语句而不是switch
语句。因此,对于Python,我可以想到一个包含