基于另一DataFrame条件读取数据并生成指定文本的技术问题

First, let's break down the issues in your original code and walk through a corrected, working solution.

Issues in Your Original Code #

1. Typo: You wrote sentances instead of sentences in the loop.
2. Missing Closing Parentheses: The print statement and between() call are missing closing parentheses, causing the SyntaxError: unexpected EOF.
3. Incorrect Iteration: Iterating directly over the DataFrame (for x in sentences) loops over column names, not rows. You need to access individual rows to get each start and stop value.
4. Passing Series to between(): The between() method expects scalar values (single numbers), but you passed entire Series (sentences['start'], sentences['stop']), which won't work for row-wise filtering.

Corrected Solution #

Here's the full working code to achieve your desired output:

import pandas as pd

# Construct the words DataFrame
words = pd.DataFrame()
words['no'] = [1,2,3,4,5,6,7,8,9]
words['word'] = ['cat', 'in', 'hat', 'the', 'dog', 'in', 'love', '!', '<3']

# Construct the sentences DataFrame
sentences = pd.DataFrame()
sentences['no'] = [1,2,3]
sentences['start'] = [1, 4, 6]
sentences['stop'] = [3, 5, 9]

# Initialize a list to hold each sentence segment
sentence_segments = []

# Iterate over each row in the sentences DataFrame
for _, row in sentences.iterrows():
    # Get start and stop values from the current row
    start_val = row['start']
    stop_val = row['stop']
    
    # Filter words where 'no' is between start and stop (inclusive)
    filtered_words = words[words['no'].between(start_val, stop_val, inclusive='both')]['word']
    
    # Join the filtered words into a single string
    segment = ' '.join(filtered_words)
    sentence_segments.append(segment)

# Join all segments with ' *** ' separator
final_output = ' *** '.join(sentence_segments)

# Print the result (matches your expected output)
print(final_output)

# Write the result to a file
with open('output.txt', 'w') as f:
    f.write(final_output)

Key Details: #

• iterrows(): This method lets us loop through each row of the sentences DataFrame, giving us access to the specific start and stop values for each segment.
• between(start_val, stop_val, inclusive='both'): Filters the words DataFrame to only include rows where no falls within the current row's range. The inclusive='both' parameter ensures both endpoints are included (this is default in newer Pandas versions, but we set it explicitly for clarity).
• String Joining: ' '.join(filtered_words) combines individual words into a space-separated segment, and ' *** '.join(sentence_segments) merges all segments into the final output string.
• File Writing: Uses a context manager (with open(...)) to safely write the result to output.txt.

Expected Output #

Running this code will produce exactly what you wanted:

cat in hat *** the dog *** in love ! <3

内容的提问来源于stack exchange，提问作者Pythonuser