[英]How to test whether a character is numeric, upper case, or lower case?
我正在嘗試運行此JavaScript。 我不斷收到錯誤消息:
ThisChar.toUpperCase() is not a function
我嘗試使用jsfiddle.net,但似乎無法解決此錯誤。 這是怎么回事?
// CREATE ARRAY OF CHARACTERS
CharacterArray = ["1", "2", "3", "a", "b", "c", "D", "E", "F", "/", "+", ")"];
// TEST CHARACTERS
function testCharacters() {
// GET ARRAY LEN
var CharacterArrayLen = CharacterArray.length;
// LOOP THROUGH ARRAY
for (i = 0; i < CharacterArrayLen; i++) {
// PARSE SINGLE CHARACTER
var ThisChar = CharacterArray.slice(i, i + 1);
if (!isNaN(ThisChar * 1)) {
alert(ThisChar + ' is numeric!');
} else {
if (ThisChar == ThisChar.toUpperCase()) {
alert(ThisChar + ' is upper case true');
} else if (ThisChar == ThisChar.toLowerCase()) {
alert(ThisChar + " is lower case");
} else {
alert(ThisChar + " is unknown");
}
}
}
}
testCharacters();
.slice
總是返回一個數組。 只需訪問元素:
var ThisChar = CharacterArray[i];
您不必將值乘以*1
,傳遞給isNaN
的值將隱式轉換為數字:
!isNaN(ThisChar)
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