Python修改字典值后为何频繁出现换行？新手技术求助

Hey there! Let's break down what's going on here and fix those unexpected newlines. 😊

First, Fix the Obvious Typos in Your Code #

You've got a couple of variable name mistakes that would throw errors before even hitting the newline issue:

• if splitStuff[0] in item: → should be items (your dictionary is named items, not item)
• Results[1] → this should be splitStuff[1] since you split the line into the splitStuff variable

The Root Cause of Unexpected Newlines #

When you use content = f.readlines(), every line in the resulting list includes the trailing newline character \n from the original file. For example, if a line in your file is 3!Angel\n, splitting it with split('!') gives you splitStuff[1] = "Angel\n"—the newline is still attached. When you write this value back to the file, that \n automatically creates a new line.

Even if your original file has multiple entries on a single line, any trailing newline from the line itself will carry through and cause unexpected line breaks in the output.

How to Fix It #

Here's the adjusted code with fixes for both typos and the newline problem:

items = dict()
with open(path) as f:
    # Iterate directly over the file object (more memory-efficient than readlines())
    for line in f:
        # Remove trailing newline characters before processing
        line_clean = line.rstrip('\n')
        splitStuff = line_clean.split('!')
        # Add a check to avoid index errors if a line lacks the ! separator
        if len(splitStuff) >= 2:
            key = splitStuff[0]
            value = splitStuff[1]
            if key in items:
                items[key] += ',' + value
            else:
                items[key] = value

with open(path2, 'a') as f:
    for key, value in items.items():
        # Explicitly control newlines: add \n if you want each entry on its own line, omit if not
        f.write(f"{key}!{value}\n")

Extra Tips #

• You don't need to call f.close() when using with statements—they automatically handle closing files safely, even if an error occurs.
• The len(splitStuff) >= 2 check prevents crashes if any line in your input file doesn't have the ! separator.
• Iterating directly over the file object (for line in f) uses less memory than readlines(), which is helpful for large files.

内容的提问来源于stack exchange，提问作者cybera