檢查一個字符串是否在它的末尾有一個破折號整數

Question

我需要你的幫助來處理一些正則表達式和字符串匹配。我該如何去檢查我的字符串（用var str表示）是否在最後有一個破折號和一個整數？請看下面的例子：

Example 1: 

var str = "test101-5" 

evaluate the str and check if it end with a dash and an integer { returns true } 

Example 2: 

var str = "ABC-DEF-GHI-4" 

evaluate the str and check if it end with a dash and an integer { returns true } 


Example 3: 

var str = "test101" 

evaluate the str and check if it end with a dash and an integer { returns false } 

Answer 1

您可以使用.test()與下面的正則表達式：

var str = "ABC-DEF-GHI-4"; 
 
console.log(/-\d$/.test(str)); // true 
 

 
str = "test101"; 
 
console.log(/-\d$/.test(str)); // false

的$將需要匹配的字符串末尾只發生。

Answer 2

您可以使用捕獲組獲取最後一位數字。

const 
 
    regex = /-(\d)$/, 
 
    tests = [ 
 
    'test101-5', 
 
    'ABC-DEF-GHI-4', 
 
    'test101' 
 
    ]; 
 
    
 
tests.forEach(test => { 
 
    const 
 
    // Index 0 will have the full match text, index 1 will contain 
 
    // the first capture group. When the string doesn't match the 
 
    // regex, the value is null. 
 
    match = regex.exec(test); 
 
    
 
    if (match === null) { 
 
    console.log(`The string "${test}" doesn't match the regex.`); 
 
    } else { 
 
    console.log(`The string "${test}" matches the regex, the last digit is ${match[1]}.`); 
 
    } 
 
});

正則表達式執行以下操作：

-  // match the dash 
( // Everything between the brackets is a capture group 
    \d // Matches digits only 
) 
$  // Match the regex at the end of the line.