列表的get()的惯用python等效项是什么? [英] What's the idiomatic python equivalent of get() for lists?

问题描述

如果字典中不存在键，则默认情况下在字典上调用get(key)将返回None.列表的惯用等效项是什么，例如，如果列表的大小至少为传入索引的大小，则返回该元素，否则返回None?

Calling get(key) on a dictionary will return None by default if the key isn't present in a dictionary. What is the idiomatic equivalent for a list, such that if a list is of at least size of the passed in index the element is returned, otherwise None is returned?

换句话说，此功能的惯用/紧凑版本是什么:

To rephrase, what's a more idiomatic/compact version of this function:

def get(l, i):
    if i < len(l):
        return l[i]
    else:
        return None

推荐答案

您的实现是突如其来样式.执行代码并捕获错误相反，这是pythonic:

Your implementation is Look Before You Leap-style. It's pythonic to execute the code and catch errors instead:

def get(l, i, d=None):
    try:
        return l[i]
    except IndexError:
        return d

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