Java如何在空格或'-'前后有字符时使用split()分割字符串

Got it, let's tackle this problem exactly as you described: you want to split a string only when there's a - or space that has characters both before and after it. Leading/trailing separators (like a space at the start, - at the end) shouldn't trigger a split—only the ones sandwiched between actual characters count.

The Regex Approach #

The perfect tool here is a regular expression with lookaround assertions—they let us check what's before/after the separator without including those characters in the match. Here's the pattern we'll use:

(?<=\S)[- ](?=\S)

Let's break down what each part does:

• (?<=\S): A positive lookbehind that ensures the character immediately before our separator is a non-whitespace character (\S = any character that's not a space/tab/newline)
• [- ]: Matches either a - or a space (we put - first in the character set to avoid it being interpreted as a range)
• (?=\S): A positive lookahead that ensures the character immediately after our separator is also a non-whitespace character

Example Code (Python) #

Here's how you can implement this in Python:

import re

def split_on_valid_separators(input_str):
    # Split using our regex pattern
    return re.split(r'(?<=\S)[- ](?=\S)', input_str)

# Test all your example cases
test_cases = [
    " test", "-test", "test test", " test test", "test-", "test-test", "a-test"
]

for case in test_cases:
    result = split_on_valid_separators(case)
    print(f"Input: '{case}' → Output: {result}")

Test Output:

Input: ' test' → Output: [' test']
Input: '-test' → Output: ['-test']
Input: 'test test' → Output: ['test', 'test']
Input: ' test test' → Output: [' test', 'test']
Input: 'test-' → Output: ['test-']
Input: 'test-test' → Output: ['test', 'test']
Input: 'a-test' → Output: ['a', 'test']

Example Code (JavaScript) #

If you're working in JavaScript, the logic is identical—just use the same regex with split():

function splitOnValidSeparators(inputStr) {
    return inputStr.split(/(?<=\S)[- ](?=\S)/);
}

// Test cases
const testCases = [
    " test", "-test", "test test", " test test", "test-", "test-test", "a-test"
];

testCases.forEach(case => {
    const result = splitOnValidSeparators(case);
    console.log(`Input: '${case}' → Output: ${JSON.stringify(result)}`);
});

Key Notes #

• This approach preserves any leading/trailing whitespace or separators in your input string, since we're only splitting on the valid middle separators.
• If you need to handle other whitespace characters (like tabs or newlines), replace the space in the regex with \s (which matches any whitespace), making the pattern (?<=\S)[-\s](?=\S).

内容的提问来源于stack exchange，提问作者dechiic