Let's figure out why your inline loop is throwing a SyntaxError, then get it working properly.

Why Your Current Code Fails #

Python's list comprehensions only accept expressions (code that produces a value), not statements like variable assignments (=). That line sentss2[aa][cc]=findtext[0] is an assignment statement, which doesn't belong in a comprehension. Also, your original loop uses the lowercase version of findtext[0] as the replacement, but your inline code incorrectly includes the original findtext[0] instead of just the lowercase value.

Working Inline Implementation #

If you’re set on rewriting the loop as an inline comprehension (quick heads-up: for operations that modify existing lists like this, a regular for loop is usually easier to read), here’s the correct code:

[sentss2[aa].__setitem__(cc, findtext[0].lower()) for aa, cc in zip(sentNum, wordnum)]

What’s Happening Here #

• When you do sentss2[aa][cc] = value, Python under the hood calls sentss2[aa].__setitem__(cc, value) — this method does the assignment, and it’s an expression (even though it returns None) that we can use in the comprehension.
• We loop through the pairs of sentence indexes (aa) and word indexes (cc) from zip(sentNum, wordnum), just like your original loop.
• This will create a list filled with None values (since __setitem__ doesn’t return anything useful), but it will correctly update the sentss2 list in-place, exactly like your original loop did.

A Better (More Readable) Option #

While the inline version works, don’t overlook that your original for loop is way clearer for anyone else reading your code (or future you!):

for aa, cc in zip(sentNum, wordnum):
    sentss2[aa][cc] = findtext[0].lower()

There’s no speed difference between the two — both run in the same time. Prioritizing readability over "conciseness" is almost always the better call here.

内容的提问来源于stack exchange，提问作者StatguyUser