Python else语句缩进错误求助：替换4空格仍报语法错

Hey there, let's break down what's causing your syntax error and fix it step by step:

1. First, Fix the Constructor Method #

You've written def _init_(self): for your class constructor, but Python requires double underscores for special methods like the constructor. Change it to:

def __init__(self):
    self.plates = []

Without this fix, your self.plates list won't be initialized properly, which will cause issues with methods like isEmpty() later on.

2. Complete the Truncated if Condition #

Your code snippet cuts off mid-if statement:

if ((self.isEmpty()) or (self.plates[len(self.plates...

Python can't parse an incomplete if condition, so it throws a syntax error when it hits the else clause. Based on your stackOfPlates class purpose, you likely want to check if either the stack collection is empty, or the last stack in the collection is at capacity. Here's the complete condition:

if self.isEmpty() or len(self.plates[-1]) >= self.cap:

3. Verify Indentation Alignment #

Even if you've switched to 4-space indents, make sure your else clause is exactly aligned with its corresponding if statement. For example:

def push(self, item):
    if self.isEmpty() or len(self.plates[-1]) >= self.cap:
        new_stack = Stack()
        new_stack.push(item)
        self.plates.append(new_stack)
    else:
        self.plates[-1].push(item)

In Sublime Text 3, you can enable View > Show White Space and Tab to visually confirm you're not mixing spaces and tabs, and that all indent levels are consistent.

Full Corrected Code Example #

Here's how your class should look with these fixes:

from Stack import Stack

class StackOfPlates:
    cap = 4

    def __init__(self):
        self.plates = []

    def isEmpty(self):
        return self.plates == []

    def push(self, item):
        if self.isEmpty() or len(self.plates[-1]) >= self.cap:
            new_stack = Stack()
            new_stack.push(item)
            self.plates.append(new_stack)
        else:
            self.plates[-1].push(item)

These changes should resolve the syntax error with your else statement. Let me know if you run into any other kinks!

内容的提问来源于stack exchange，提问作者wAnder