如何替换 ArrayList 的特定部分？

Question

所以我这里有一个ArrayList ：

story.add("Select the type of bread you want to use. Many prefer the taste of [Color] bread, while others prefer [Noun1] bread because it is healthy.");
story.add("Choose the flavor of Jam/Jelly. I personally prefer [Food] jam, but you can use whatever you want.");
story.add(" Choose the type of peanut butter - either [Adjective1] or [Adjective2].");
story.add("Take out [Number] slice(s) of bread.");
story.add(" Use a [Noun2] to [Verb1] the jam all over on of the pieces of bread.");
story.add(" Now [Verb2] the peanut butter on the other piece of bread.");
story.add("Put them together, and you have a PB&J [Verb3].");

我正在尝试替换ArrayList的单个部分。 例如，我想用实际颜色替换[Color]而不替换整个ArrayList 。 这可能吗？

谢谢。

Answer 1

使用ListIterator ，因此您可以在迭代时替换该值：

for (ListIterator<String> iter = story.listIterator(); iter.hasNext(); ) {
    String line = iter.next();
    line = line.replace("[Color]", "BLUE");
    iter.set(line);
}

story.forEach(System.out::println);

输出

Select the type of bread you want to use. Many prefer the taste of BLUE bread, while others prefer [Noun1] bread because it is healthy.
Choose the flavor of Jam/Jelly. I personally prefer [Food] jam, but you can use whatever you want.
 Choose the type of peanut butter - either [Adjective1] or [Adjective2].
Take out [Number] slice(s) of bread.
 Use a [Noun2] to [Verb1] the jam all over on of the pieces of bread.
 Now [Verb2] the peanut butter on the other piece of bread.
Put them together, and you have a PB&J [Verb3].

如果你想在一次迭代中替换许多占位符，那么这样做（Java 9+）：

Map<String, String> map = new HashMap<>();
map.put("Color", "BLUE");
map.put("Adjective1", "SMOOTH");
map.put("Adjective2", "CHUNKY");
map.put("Number", "THREE");

Pattern p = Pattern.compile("\\[([^\\]]+)\\]");
for (ListIterator<String> iter = story.listIterator(); iter.hasNext(); ) {
    String line = iter.next();
    line = p.matcher(line).replaceAll(mr -> map.getOrDefault(mr.group(1), mr.group(0)));
    iter.set(line);
}

输出

Select the type of bread you want to use. Many prefer the taste of BLUE bread, while others prefer [Noun1] bread because it is healthy.
Choose the flavor of Jam/Jelly. I personally prefer [Food] jam, but you can use whatever you want.
 Choose the type of peanut butter - either SMOOTH or CHUNKY.
Take out THREE slice(s) of bread.
 Use a [Noun2] to [Verb1] the jam all over on of the pieces of bread.
 Now [Verb2] the peanut butter on the other piece of bread.
Put them together, and you have a PB&J [Verb3].

Answer 2

我假设这是一个String的 ArrayList ，如下所示：

ArrayList<String> story = new ArrayList<String>();
story.add("Select the type of bread you want to use. Many prefer the taste of [Color] bread, while others prefer [Noun1] bread because it is healthy.");
...

在这种情况下，您需要将 CharSequence [Color]替换为您的新值：

story.get(0).replace("[Color]", "yellow");

如果你想用替换的值覆盖原始的 ArrayList 你会做...

story.set(0, story.get(0).replace("[Color]", "yellow"));

Answer 3

好吧，您不必遍历 Array。也可以使用stream来完成。 您可以使用带有 .stream() 方法的一行代码更改集合中的任何值。

    story.stream().map( n ->n.replace("VALUE_YOU_WANT_TO_REPLACE","VALUE_YOU_WANT_TO_BE_REPLACED")).collect(Collectors.toList());

例如，如果您想用“蓝色”替换“[颜色]”

    story = (ArrayList<String>) story.stream().
        map(n ->n.replace("[Color]","BLUE")).collect(Collectors.toList());

Answer 4

你可以在一条短线中完成...

给定您想要的值的地图：

Map<String, String> map = Map.of("[Color]", "green", "[Food]", "fries"); // etc

这进行了转换：

map.forEach((k, v) -> story.replaceAll(s -> s.replace(k, v)));

有关List#replaceAll 的信息，请参阅 javadoc

请注意，此解决方案不使用正则表达式匹配的。