非正则表达式实现标点拆分与单词拼接的代码调试问题

Let's break down what's wrong with your current code and fix it step by step to meet your requirement.

What's Wrong with Your Current Code #

• Incorrect splitting logic: Using sentence.split('_') splits the entire input at every underscore—including the spaces around them. For your input, this creates ["Democr ", "acy , is overrat ", "ed ."], and joining these gives messy text with extra spaces instead of properly combining word fragments.
• Misplaced, useless condition checks: The variable c starts as an empty string, so c not in punctuation is always true. The elif block never runs unless you modify c—and even if it did, looping through every character in the sentence and splitting on each c would just spam random lists, which explains your 29-list output.
• No punctuation spacing handling: Your code doesn't address the core need to attach punctuation directly to the preceding word (like turning acy , into acy,).

Step-by-Step Fix #

We'll skip regex entirely and focus on two key tasks: combining word fragments separated by _ (space-underscore-space), and cleaning up punctuation spacing to match your expected output.

Here's the corrected code:

sentence = input().strip()
# Define all punctuation marks we need to adjust
punctuation = {"!", "\"", "#", "$", "%", "&", "'", "(", ")", "*", "+", ",", "-", ".", "/", ":", ";", "<", "=", ">", "?", "@", "[", "\\", "]", "^", "`", "{", "|", "}", "~"}

# Step 1: Merge word fragments split by " _ "
processed = sentence.replace(" _ ", "")

# Step 2: Remove spaces before punctuation to attach them to words
for p in punctuation:
    processed = processed.replace(f" {p}", p)

print(processed)

How It Works #

1. Combining word fragments: The replace(" _ ", "") call targets the exact pattern separating your word parts. For your input, Democr _acy becomes Democracy and overrat _ed becomes overrated.
2. Cleaning punctuation: We loop through each punctuation mark and replace any instance of [space][punctuation] with just the punctuation. This fixes acy , to acy, and ed . to ed. while leaving normal spaces between words (like is overrated) intact.

Testing with your input Democr _acy , is overrat _ed . gives the expected output:

Democracy, is overrated.

内容的提问来源于stack exchange，提问作者0phase