Question

如何替换列表中索引[3]后的每个单词？

例如，我需要将第一个单词更改为“How's”，将第二个单词更改为“it”，将第三个单词更改为“going？”。然后，我需要在索引[3]之后将每个单词更改为“yo”：

namespace App\Console\Command;

use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\Console\Input\InputArgument;
use Symfony\Component\Console\Input\InputOption;
use Symfony\Component\Process\Process;
use Symfony\Component\Process\Exception\ProcessFailedException;

class ComposerCommand extends Command {

    /**
     * Configures the console Application
     *
     */
    protected function configure() {
        $this->setName("composer:install")
            ->setDescription("Composer install inside a symfony console.")
            ->addOption('path', 'p', InputOption::VALUE_REQUIRED)
            ->setHelp(<<<EOT
The <info>composer:install</info> command makes "composer install"
EOT
            );
    }

    /**
     * Executes the console Application
     *
     * @param InputInterface $input
     * @param OutputInterface $output
     * @throws \Exception
     */
    protected function execute(InputInterface $input, OutputInterface $output) {
        try {
            $path = $input->getOption('path');

            $process = new Process('php composer.phar install --no-interaction');
            $process->setWorkingDirectory($path);
            $process->run();

            // executes after the command finishes
            if (!$process->isSuccessful()) {
                throw new ProcessFailedException($process);
            }

            $output->writeln($process->getOutput());
            $output->writeln($process->getErrorOutput());
        } catch (\Exception $e) {
            throw new \Exception($e);
        }

    }
}

这是我到目前为止所做的：

input = "My name is bla bla bla?" 

output = "How's it going? Yo! Yo! Yo!"

到目前为止我只得到：

def hellohello(input):
    if type(input) != str:
        return "Input has to be string"
    else:
        new_input = input.split(' ')
        if len(input) <= 3:
            return "How's it going?"
        else:
            new_input[0] = "How's "
            new_input[1] = "it "
            new_input[2] = "going? "
            new_input[3:] = ["Yo! "]
            output = ''.join(new_input)
            return output

print hellohello("why is this not printing more yo")

Answer 1

叫我懒惰，但我可能首先创建一个长度为len(new_input)的列表，其中包含'Yo!'，然后交换["How's", "it", "going?"] ...

>>> s = "My name is bla bla bla?"
>>> new_input = s.split()
>>> output = ['Yo!'] * len(new_input)
>>> output[:3] = ["How's", "it", "going?"]
>>> output
["How's", 'it', 'going?', 'Yo!', 'Yo!', 'Yo!']

您的代码存在问题：

new_input[3:] = ["Yo! "]

您正在使用单个元素替换多个元素。您可以通过执行new_input[3:] = ["Yo! "] * (len(new_input) - 3)来修复代码，这将创建一个"Yo! "列表，其长度与您尝试替换的子列表的长度相同。

^{您可能已经注意到我使用的是s.split()而不是s.split(' ')。 s.split()与s.split(None)相同，它在连续的空白行（包括换行符和制表符）上分割。基本上，'foo bar\tbaz'.split()会产生['foo', 'bar', 'baz']，而'foo bar\tbaz'.split(' ')会产生['foo', '', 'bar\tbaz']}

Answer 2

试试这个：

def hellohello(input):
    if type(input) != str:
        return "Input has to be string"
    else:
        new_input = input.split(' ')
        if len(input) <= 3:
            return "How's it going?"
        else:
            new_input[0] = "How's"
            new_input[1] = "it"
            new_input[2] = "going?"
            for currentIndex in xrange(3, len(new_input)):
                new_input[currentIndex] = "Yo!"
            output = ' '.join(new_input)
            return output

print hellohello("why is this not printing more yo")
print hellohello("why is this")
print hellohello("why is this yep")

输出：

How's it going? Yo! Yo! Yo! Yo!
How's it going?
How's it going? Yo!

通过执行new_input[3:] = ["Yo! "]，您只需将所有字符串标记的子数组（在由split分隔的数组中）从索引3替换为具有单个字符串“Yo！”的最后一个索引，自己替换每个数组项。基本上，您引用了数组的整个切片（3:）而不是单个项目。

[编辑：基于正确评论的更新解决方案，不需要使用切片和索引计算，还添加了之前出错的解释]

替换列表中索引k后的每个单词

2 个答案: