Python程序找到字符串中所有单词的起始和结束索引

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在Python中,我们经常需要处理字符串并对其进行各种操作。其中一个常见的任务是找到字符串中所有单词的起始和结束索引。在本文中,我将详细介绍如何编写一个Python程序来实现这个任务。

要找到字符串中所有单词的起始和结束索引,我们可以使用正则表达式来匹配单词。Python中的re模块提供了对正则表达式的支持,我们可以利用它来实现我们的目标。

下面是一个示例程序,演示了如何找到字符串中所有单词的起始和结束索引:

import re

def find_word_indices(text):
    pattern = r"\b\w+\b"  # 匹配一个单词的正则表达式模式
    word_indices = [
Python 算法基础篇之字符串操作:索引、切片、常用方法 字符串是一种常见的数据类型,在 Python 中对字符串进行操作是非常常见的需求。本篇博客将介绍字符串的基本概念,包括索引、切片和常用方法,并通过实例代码演示它们的应用。 阅读详情

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% Dropout fraction opts.numepochs = 1; % Number of full sweeps through dataopts.batchsize = 100; % Take a mean gradient step over this many samplesnn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');%% ex4 neural net with sigmoid activation functionrand('state',0)nn = nnsetup([784 100 10]);nn.activation_function = 'sigm'; % Sigmoid activation functionnn.learningRate = 1; % Sigm require a lower learning rateopts.numepochs = 1; % Number of full sweeps through dataopts.batchsize = 100; % Take a mean gradient step over this many samplesnn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');%% ex5 plotting functionalityrand('state',0)nn = nnsetup([784 20 10]);opts.numepochs = 5; % Number of full sweeps through datann.output = 'softmax'; % use softmax outputopts.batchsize = 1000; % Take a mean gradient step over this many samplesopts.plot = 1; % enable plottingnn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');%% ex6 neural net with sigmoid activation and plotting of validation and training error% split training data into training and validation datavx = train_x(1:10000,:);tx = train_x(10001:end,:);vy = train_y(1:10000,:);ty = train_y(10001:end,:);rand('state',0)nn = nnsetup([784 20 10]); nn.output = 'softmax'; % use softmax outputopts.numepochs = 5; % Number of full sweeps through dataopts.batchsize = 1000; % Take a mean gradient step over this many samplesopts.plot = 1; % enable plottingnn = nntrain(nn, tx, ty, opts, vx, vy); % nntrain takes validation set as last two arguments (optionally)[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');```[![Bitdeli Badge](https://d2weczhvl823v0.cloudfront.net/rasmusbergpalm/deeplearntoolbox/trend.png)](https://bitdeli.com/free "Bitdeli Badge")

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