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var contacts = [
{
"firstName": "Akira",
"lastName": "Laine",
"number": "0543236543",
"likes": ["Pizza", "Coding", "Brownie Points"]
},
{
"firstName": "Harry",
"lastName": "Potter",
"number": "0994372684",
"likes": ["Hogwarts", "Magic", "Hagrid"]
},
{
"firstName": "Sherlock",
"lastName": "Holmes",
"number": "0487345643",
"likes": ["Intriguing Cases", "Violin"]
},
{
"firstName": "Kristian",
"lastName": "Vos",
"number": "unknown",
"likes": ["Javascript", "Gaming", "Foxes"]
}];
function lookUpProfile(firstName, prop){
for (var i = 0; i < contacts.length; i++){
if (firstName === contacts[i].firstName) {
if (contacts[i][prop]) {
return contacts[i][prop];
} else {
return "No such property";
}
}
}
return "No such contact";
}
lookUpProfile("Akira", "likes");
此代碼運行完美。但如果我使用if(firstName === contacts [i] [firstName])而不是if(firstName === contacts [i] .firstName),它不起作用。爲什麼?由於點或括號都可用於訪問對象屬性。爲什麼if語句不接受括號記號而不是點記號?
可能重複[JavaScript屬性訪問:點符號與括號?](http://stackoverflow.com/questions/4968406/javascript-property-access-dot-notation-vs-brackets) – Thilo
同意重複我認爲這個答案更適合你的問題:http://stackoverflow.com/a/4968460/1695393 – dubes