Javascript ELSE語句無論IF語句如何運行

Question

非常簡單的代碼片段（我是編程新手），我很難過。

無論IF語句是否爲真，控制檯爲什麼每次循環都會返回0？

例如，IF語句運行，找到一個匹配並將1寫入控制檯，但隨後ELSE語句也會運行，重置變量「count」。

//Snippet of the array of objects, that the program searches through 
 
var students = [ 
 
    { 
 
    name: 'Dave', 
 
    track: 'Front End Development', 
 
    achievements: 158, 
 
    points: 14730 
 
    }, 
 
    { 
 
    name: 'John', 
 
    track: 'Full Stack', 
 
    achievements: '24', 
 
    points: '2450' 
 
    } 
 
]; 
 

 
//Declaring variables 
 
var message = ''; 
 
var student; 
 
var count = 0; 
 
var name; 
 
var search; 
 

 

 
while (true) { 
 
\t search = prompt("Enter a name to see their report, or type 'quit' to exit."); 
 
\t if (search.toUpperCase() == 'QUIT' || search.toUpperCase() == null) { 
 
\t \t console.log(8); 
 
\t \t break; 
 
\t } 
 
\t for (i = 0; i < students.length; i++) { 
 
\t \t student = students[i]; 
 
\t \t name = search.toUpperCase(); 
 
\t \t if (name == student.name.toUpperCase()) { 
 
\t \t \t count ++; 
 
\t \t \t console.log(count); 
 
\t \t } else { 
 
\t \t \t count = 0; 
 
\t \t \t console.log(count); 
 
\t \t } 
 
\t } 
 
}

Answer 1

我不能立即看到你的問題的原因，的count = 0在else分支復位看起來錯誤的，如果名字重複會造成問題，但是你至少應該得到1一次在第一場比賽，而你斷言它總是返回0。

無論哪種方式，寫這將是更習慣的方法：

var uSearch = search.toUpperCase(); 
var count = students.filter(function(student) { 
    return student.name.toUpperCase() === uSearch; 
}).length; 

Answer 2

移動count = 0;外for loop的。從一個空的櫃檯開始。

Answer 3

權，如馬特說......你可以先初始化計數= 0外循環。在條件被搶先調試之後，我還會添加一行console.log(name)。

count = 0 
for (i = 0; i < students.length; i++) { 
    student = students[i]; 
    name = search.toUpperCase(); 

    # show me the "name" before running condition 
    console.log("name pulled from search: ",name) 

    if (name == student.name.toUpperCase()) { 
    count++; 
    console.log(count); 
    } else { 
    count = 0; 
    console.log(count); 
    } 
} 

打印"name"應該給你一個想法，條件如何匹配。

Answer 4

這是比較兩個數組值的示例代碼。

var count = 0; 

var students = [ 
    { name:"string 1", value:"this", other: "that" }, 
    { name:"string 2", value:"this", other: "that" } 
]; 

var search = [ 
    { name:"string 1", value:"this", other: "that" }, 
    { name:"string 3", value:"this", other: "that" } 
]; 

for (var i = 0; i < students.length; i++) { 

for (var j = 0; j < search.length; j++) { 

    var student = students[i].name.toUpperCase(); 

    var names = search[j].name.toUpperCase(); 

    if (names == student) { 
    count++; 

    console.log(count); 
    } else { 
    count = 0; 

    console.log(count); 
    } 
    } 
}