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strings - Expand concept by newline and text blocks #2941

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16b9df0
strings - Expand concept by newline and text blocks
fapdash Apr 27, 2025
1b9ca23
Rewording
fapdash Apr 27, 2025
909b87e
Fix markdown linting errors
fapdash Apr 27, 2025
0e09521
Clarify when to use system dependent line separators
fapdash Apr 27, 2025
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4 changes: 3 additions & 1 deletion concepts/strings/.meta/config.json
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Original file line number Diff line number Diff line change
Expand Up @@ -3,5 +3,7 @@
"authors": [
"mirkoperillo"
],
"contributors": []
"contributors": [
"fapdash"
]
}
38 changes: 36 additions & 2 deletions concepts/strings/about.md
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Expand Up @@ -22,6 +22,29 @@ String escaped = "c:\\test.txt";
// => c:\test.txt
```

To put a newline character in a string, use the `\n` escape code (`\r\n` on Windows):

```java
"<html>\n <body>\n <h1>Hello, World!</h1>\n </body>\n</html>\n"
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Thought to assign to variable to keep consistent with the other examples.

Suggested change
"<html>\n <body>\n <h1>Hello, World!</h1>\n </body>\n</html>\n"
String multilineHtml = "<html>\n <body>\n <h1>Hello, World!</h1>\n </body>\n</html>\n";

```

For code that should work on varying operating systems Java offers [`System.lineSeparator()`][system-line-separator], which returns the system-dependent line separator string.
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Wouldn't using the System.lineSeparator require string concatenation that comes later? I wonder if it would flow better if this section came after string concatenation. Other than that, I think it would be handy to have an example showing how to use this.

This is important if you're writing to files that will be read on the same system.

To comfortable work with texts that contain a lot of newlines you can use [Text Blocks][text-blocks].
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Suggested change
To comfortable work with texts that contain a lot of newlines you can use [Text Blocks][text-blocks].
To comfortably work with texts that contain a lot of newlines you can use [Text Blocks][text-blocks].

These multi-line strings are delimited by triple double quote (`"`) characters.

```java
String multilineHtml = """
<html>
<body>
<h1>Hello, World!</h1>
</body>
</html>
""";
// => "<html>\n <body>\n <h1>Hello, World!</h1>\n </body>\n</html>\n"
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@kahgoh kahgoh May 30, 2025 •
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I thought the result string line looks a little strange with it all being on one line with the \n because the multi-line template is expressed over multiple lines. Perhaps we could remove it?

Suggested change
// => "<html>\n <body>\n <h1>Hello, World!</h1>\n </body>\n</html>\n"

```

Finally, there are many ways to concatenate a string.
The simplest one is the `+` operator:

Expand All @@ -35,15 +58,26 @@ For any string formatting more complex than simple concatenation, `String.format

```java
String name = "Jane";
String.format("Hello %s!",name);
String.format("Hello %s!", name);
// => "Hello Jane!"
```

Other possibilities are:
The conversion `%n` in a format string inserts a system-dependent line separator.

```java
String name = "Jane";
String.format("Hello,%n%s!", name);
// => "Hello,\nJane!" (Linux, macOS)
// => "Hello,\r\nJane!" (Windows)
```

Other possibilities to build more complex strings are:

- use [`StringBuilder` class][string-builder]
- use [`String.concat` method][string-concat]

[string-class]: https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/String.html
[text-blocks]: https://openjdk.org/projects/amber/guides/text-blocks-guide
[string-builder]: https://docs.oracle.com/javase/tutorial/java/data/buffers.html
[string-concat]: https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#concat-java.lang.String-
[system-line-separator]: https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/lang/System.html#lineSeparator()