如何替換 ArrayList 的特定部分？

Question

所以我這里有一個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].");

我正在嘗試替換ArrayList的單個部分。 例如，我想用實際顏色替換[Color]而不替換整個ArrayList 。 這可能嗎？

謝謝。

Answer 1

使用ListIterator ，因此您可以在迭代時替換該值：

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);

輸出

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換許多占位符，那么這樣做（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);
}

輸出

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

我假設這是一個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.");
...

在這種情況下，您需要將 CharSequence [Color]替換為您的新值：

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

如果你想用替換的值覆蓋原始的 ArrayList 你會做...

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

Answer 3

好吧，您不必遍歷 Array。也可以使用stream來完成。 您可以使用帶有 .stream() 方法的一行代碼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“藍色”替換“[顏色]”

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

Answer 4

你可以在一條短線中完成...

給定您想要的值的地圖：

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

這進行了轉換：

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

有關List#replaceAll 的信息，請參閱 javadoc

請注意，此解決方案不使用正則表達式匹配的。