如何用Python统计字符串中"dance"的出现次数（排除"dances"）

Great question! You can absolutely condense your logic into a single line of Python code—here are a couple of straightforward ways to do it:

Option 1: Combine Your Original Logic #

Your initial approach is solid, and you can just merge the two count() calls into one expression without repeating code unnecessarily:

var = "Boys dance, girls dance, he dances, she dances"
count = var.count("dance") - var.count("dances")
print(count)  # Output: 2

If you really want to cram everything into one line (though readability should be a priority), you can even define the string and calculate the count in a single statement:

count = "Boys dance, girls dance, he dances, she dances".count("dance") - "Boys dance, girls dance, he dances, she dances".count("dances")

But the first version is cleaner—no need to duplicate the string.

Option 2: Use Regex for Exact Word Matching #

If you want to ensure you only match the standalone word "dance" (and not accidentally catch it as part of longer words like "dances"), regular expressions are a great tool:

import re
count = len(re.findall(r'\bdance\b', "Boys dance, girls dance, he dances, she dances"))
print(count)  # Output: 2

The \b in the regex pattern stands for a word boundary, so it will only match "dance" when it's a complete word, not when it's followed by an 's' (or any other characters that make it part of a longer word).

Both methods will give you the correct count of 2 in a more concise way than your original multi-line code.

内容的提问来源于stack exchange，提问作者puregeek