Javascript-如何获取数组中的第一个元素?
例如:Javascript-如何获取数组中的第一个元素?,javascript,arrays,highcharts,Javascript,Arrays,Highcharts,例如: var myArray = ['e', {pluribus: 'unum'}]; 如何获得第一个“e” 我的实际数组如下所示: ({'U.S., MCC':{score:"88.88", url:"http://ati.publishwhatyoufund.org/donor/usmcc/"}, GAVI:{score:"87.26", url:"http://ati.publishwhatyoufund.org/donor/gavi/"}, 'UK, DFID':{score:"83
var myArray = ['e', {pluribus: 'unum'}];
如何获得第一个“e”
我的实际数组如下所示:
({'U.S., MCC':{score:"88.88", url:"http://ati.publishwhatyoufund.org/donor/usmcc/"}, GAVI:{score:"87.26", url:"http://ati.publishwhatyoufund.org/donor/gavi/"}, 'UK, DFID':{score:"83.49", url:"http://ati.publishwhatyoufund.org/donor/ukdfid/"}, UNDP:{score:"83.38", url:"http://ati.publishwhatyoufund.org/donor/undp/"}, 'World Bank, IDA':{score:"73.81", url:"http://ati.publishwhatyoufund.org/donor/world-bank-ida/"}, 'Global Fund':{score:"70.65", url:"http://ati.publishwhatyoufund.org/donor/global-fund/"}})
我需要知道名字。i、 e‘U.S.,MCC’,然后是分数和url——我在highcharts中将其用作图表中的数据点
我知道这应该很简单,但我是个彻头彻尾的傻瓜
感谢要从数组中获取第一个元素,只需使用以下命令:
myArray[0]
请注意,0
指向数组中的第一个元素。数组是零索引的
看一看,了解更多
然而,你拥有的不是数组,而是对象。您无法使用数字键访问这些内容(如
0、1、2
等)
要获取对象的第一个元素,必须使用“键”访问该值。假设:
var myObject = {'U.S., MCC':{score:"88.88", url:"http://ati.publishwhatyoufund.org/donor/usmcc/"}, GAVI:{score:"87.26", url:"http://ati.publishwhatyoufund.org/donor/gavi/"}, 'UK, DFID':{score:"83.49", url:"http://ati.publishwhatyoufund.org/donor/ukdfid/"}, UNDP:{score:"83.38", url:"http://ati.publishwhatyoufund.org/donor/undp/"}, 'World Bank, IDA':{score:"73.81", url:"http://ati.publishwhatyoufund.org/donor/world-bank-ida/"}, 'Global Fund':{score:"70.65", url:"http://ati.publishwhatyoufund.org/donor/global-fund/"}}
然后:
将是:
{score:"88.88", url:"http://ati.publishwhatyoufund.org/donor/usmcc/"}
或者,作为一个更简单的例子:
var foo = {
'bar': 1,
'wut': {'nested': 'you can nest objects! (and arrays, etc)'}
baz: 'Objects, woo!', // Quotes around keys aren't mandatory, unless you have
} // spaces in the keys: 'quotes mandatory'
foo['bar'] // 1
foo.wut.nested // 'you can nest objects! (and arrays, etc)'
foo.baz // 'Objects, woo!' (you don't have to use the square brackets,
// if the key is a simple string (No spaces))
请查看以了解更多关于这些的信息
现在,实际获取该对象中的“第一个”元素是很困难的,因为对象没有排序。(即使他们看起来是这样的。) 您可以在中使用“
for…”循环对象,但不能保证这些项目在不同的浏览器上以相同的顺序显示:
for (var key in myObject) {
if (myObject.hasOwnProperty(key)) { // Make sure it's a proper element on the object, not a prototype function.
// key == ''U.S., MCC', for example,
doSomethingWith(myObject[key]);
}
}
您可以按排序顺序对对象进行迭代,但有一些是这样的。要从数组中获取第一个元素,只需使用以下命令:
myArray[0]
请注意,0
指向数组中的第一个元素。数组是零索引的
看一看,了解更多
然而,你拥有的不是数组,而是对象。您无法使用数字键访问这些内容(如0、1、2
等)
要获取对象的第一个元素,必须使用“键”访问该值。
假设:
var myObject = {'U.S., MCC':{score:"88.88", url:"http://ati.publishwhatyoufund.org/donor/usmcc/"}, GAVI:{score:"87.26", url:"http://ati.publishwhatyoufund.org/donor/gavi/"}, 'UK, DFID':{score:"83.49", url:"http://ati.publishwhatyoufund.org/donor/ukdfid/"}, UNDP:{score:"83.38", url:"http://ati.publishwhatyoufund.org/donor/undp/"}, 'World Bank, IDA':{score:"73.81", url:"http://ati.publishwhatyoufund.org/donor/world-bank-ida/"}, 'Global Fund':{score:"70.65", url:"http://ati.publishwhatyoufund.org/donor/global-fund/"}}
然后:
将是:
{score:"88.88", url:"http://ati.publishwhatyoufund.org/donor/usmcc/"}
或者,作为一个更简单的例子:
var foo = {
'bar': 1,
'wut': {'nested': 'you can nest objects! (and arrays, etc)'}
baz: 'Objects, woo!', // Quotes around keys aren't mandatory, unless you have
} // spaces in the keys: 'quotes mandatory'
foo['bar'] // 1
foo.wut.nested // 'you can nest objects! (and arrays, etc)'
foo.baz // 'Objects, woo!' (you don't have to use the square brackets,
// if the key is a simple string (No spaces))
请查看以了解更多关于这些的信息
现在,实际获取该对象中的“第一个”元素是很困难的,因为对象没有排序。(即使他们看起来是这样的。)
您可以在
中使用“for…”循环对象,但不能保证这些项目在不同的浏览器上以相同的顺序显示:
for (var key in myObject) {
if (myObject.hasOwnProperty(key)) { // Make sure it's a proper element on the object, not a prototype function.
// key == ''U.S., MCC', for example,
doSomethingWith(myObject[key]);
}
}
您可以按排序顺序对对象进行迭代,但有一些是这样的。尝试使用这种情况:
var myObj = {'U.S., MCC':{score:"88.88", url:"http://ati.publishwhatyoufund.org/donor/usmcc/"}, GAVI:{score:"87.26", url:"http://ati.publishwhatyoufund.org/donor/gavi/"}, 'UK, DFID':{score:"83.49", url:"http://ati.publishwhatyoufund.org/donor/ukdfid/"}, UNDP:{score:"83.38", url:"http://ati.publishwhatyoufund.org/donor/undp/"}, 'World Bank, IDA':{score:"73.81", url:"http://ati.publishwhatyoufund.org/donor/world-bank-ida/"}, 'Global Fund':{score:"70.65", url:"http://ati.publishwhatyoufund.org/donor/global-fund/"}};
for(v in myObj) {
console.log("Obj key: "+v, myObj[v]);
}
尝试使用此案例:
var myObj = {'U.S., MCC':{score:"88.88", url:"http://ati.publishwhatyoufund.org/donor/usmcc/"}, GAVI:{score:"87.26", url:"http://ati.publishwhatyoufund.org/donor/gavi/"}, 'UK, DFID':{score:"83.49", url:"http://ati.publishwhatyoufund.org/donor/ukdfid/"}, UNDP:{score:"83.38", url:"http://ati.publishwhatyoufund.org/donor/undp/"}, 'World Bank, IDA':{score:"73.81", url:"http://ati.publishwhatyoufund.org/donor/world-bank-ida/"}, 'Global Fund':{score:"70.65", url:"http://ati.publishwhatyoufund.org/donor/global-fund/"}};
for(v in myObj) {
console.log("Obj key: "+v, myObj[v]);
}
我认为真实的大小写并不是那么简单,看看OP的真实“数组”是什么样子。@dfsq:我添加了更多的信息。我认为真实的大小写并不是那么简单,看看OP的真实“数组”是什么样子。@dfsq:我添加了更多的信息。那不是数组,那是对象。那不是数组,那是对象。