javascript - 在数组 javascript 之间获取特定值？

Question

我有一个像这样的数组

0: "City1"
1: {name="sds", age="asd",....}
2: {name="sweds", age="accxsd",....}
3: {name="sdqws", age="asssd",....}
4: "City2"
... and many more

所以我需要获取index[0]和index[4]之间的元素，

我能够使用 typeof 检查 string 和 object

for(i=0; i<=arr.length; i++){
    if(typeof arr[i] == 'string'){
        ... // need to find next element eith type string
    }
}

有没有办法找到数组中值为字符串的下一个元素，这样我就可以得到它们之间的元素。

Answer 1

您可以使用 reduce 函数来使用此替代方法。

此方法构建一个对象，将对象分组到一个数组中，其中包含找到的字符串值。

var array = [ "City1", {name:"sds", age:"asd"}, {name:"sweds", age:"accxsd"}, {name:"sdqws", age:"asssd"}, "City2", {name:"sds2", age:"asd2"}, {name:"sweds2", age:"accxsd2"}, {name:"sdqws2", age:"asssd2"}];
 
 var result = array.reduce((a, c) => {
  if (typeof c === 'string') {
    a[c] = [];
    a.current = c;
  } else if (a.current !== "") { 
    a[a.current].push(c);
  }
  
  return a;
 }, {current: ""});
 delete result.current;
 
 console.log(result);

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How can I adjust to a particular String value, like if my input id 'city3', I need to get all elements between 'city3' and its next string value

上述方法通过之前找到的字符串元素对元素进行分组，因此可以直接访问所需的目标City3

var array = [ "City1", {name:"sds", age:"asd"}, {name:"sweds", age:"accxsd"}, {name:"sdqws", age:"asssd"}, "City3", {name:"sds3", age:"asd3"}, {name:"sweds3", age:"accxsd3"}, {name:"sdqws3", age:"asssd3"}, "City4", {name:"sds4", age:"asd4"}, {name:"sweds4", age:"accxsd4"}, {name:"sdqws4", age:"asssd"}];

var result = array.reduce((a, c) => {
  if (typeof c === 'string') {
    a[c] = [];
    a.current = c;
  } else if (a.current !== "") {
    a[a.current].push(c);
  }

  return a;
}, {
  current: ""
});
delete result.current;

var target = "City3";
// Now you have a direct access to find the desired target.
console.log(result[target]);

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