Python 在句串上滑动 Window

Question

我正在寻找一个滑动 window 字符串拆分器，该拆分器由 window 大小为 N 的单词组成。

输入: "I love food and I like drink" , window 尺寸 3

输出: ["I love food", "love food and", "food and I", "and I like" .....]

window滑动的所有建议都是围绕字符串的顺序，没有条款。有开箱即用的东西吗？

Answer 1

def token_sliding_window(str, size):
    tokens = str.split(' ')
    for i in range(len(tokens )- size + 1):
        yield tokens[i: i+size]

Answer 2

您可以使用具有不同偏移量的迭代器并将它们全部压缩。

>>> arr = "I love food. blah blah".split()
>>> its = [iter(arr), iter(arr[1:]), iter(arr[2:])] #Construct the pattern for longer windowss
>>> zip(*its)
[('I', 'love', 'food.'), ('love', 'food.', 'blah'), ('food.', 'blah', 'blah')]

如果你的句子很长，你可能想使用 izip，或者可能是普通的旧循环（就像在其他答案中一样）。

Answer 3

一种基于下标字符串序列的方法：

def split_on_window(sequence="I love food and I like drink", limit=4):
    results = []
    split_sequence = sequence.split()
    iteration_length = len(split_sequence) - (limit - 1)
    max_window_indicies = range(iteration_length)
    for index in max_window_indicies:
        results.append(split_sequence[index:index + limit])
    return results

示例输出：

>>> split_on_window("I love food and I like drink", 3)
['I', 'love', 'food']
['love', 'food', 'and']
['food', 'and', 'I']
['and', 'I', 'like']
['I', 'like', 'drink']

这是受@SuperSaiyan 启发的替代答案：

from itertools import izip

def split_on_window(sequence, limit):
    split_sequence = sequence.split()
    iterators = [iter(split_sequence[index:]) for index in range(limit)]
    return izip(*iterators)

示例输出：

>>> list(split_on_window(s, 4))
[('I', 'love', 'food', 'and'), ('love', 'food', 'and', 'I'), 
('food', 'and', 'I', 'like'), ('and', 'I', 'like', 'drink')]

基准：

Sequence = I love food and I like drink, limit = 3
Repetitions = 1000000
Using subscripting -> 3.8326420784
Using izip -> 5.41380286217 # Modified to return a list for the benchmark.

Python 在句串上滑动 Window

Python Sliding Window on sentence string

python

string

sliding-window

python-2.7