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digitalmars.D.learn - Printing a quoted string

reply Amit <a a.a> writes:
Hi!

I would like to print a string in the same format that I would 
write it in the code (with quotes and with special characters 
escaped). Similar to [Go's %q 
format](https://pkg.go.dev/fmt#hdr-Printing). Is there a safe, 
built-in way to do that?

For example:

```
string s = "one \"two\"\nthree four";
writeln(/* ??? */);
```

And get as output

```
"one \"two\"\nthree four"
```

Instead of

```
one "two"
three four
```
Jan 02 2022
next sibling parent reply =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
On 1/2/22 9:27 AM, Amit wrote:


 string s = "one \"two\"\nthree four";


The issue there is that the string does not contain the two characters 
\" but the single character ". So, that's a syntax issue. The solution 
is to use back ticks to tell the compiler what you really mean.


 And get as output

 ```
 "one \"two\"\nthree four"
 ```


import std.stdio;

void main() {
   string s = `one \"two\"\nthree four`;  // <-- Back ticks
   writeln(s);
}

Ali
Jan 02 2022
parent Amit <a a.a> writes:
On Sunday, 2 January 2022 at 17:33:22 UTC, Ali Çehreli wrote:

 The issue there is that the string does not contain the two 
 characters \" but the single character ". So, that's a syntax 
 issue. The solution is to use back ticks to tell the compiler 
 what you really mean.


Thank you! I think my question was misunderstood though.

I am not looking to change the **input** string (as the backticks 
would do), but the **output** string.

Like this:

```
assert(some_formatting("one \"two\"\nthree four") == `"one 
\"two\"\nthree four"`);
```

I hope this clarifies :)
Jan 02 2022
prev sibling next sibling parent reply WebFreak001 <d.forum webfreak.org> writes:
On Sunday, 2 January 2022 at 17:27:53 UTC, Amit wrote:

 Hi!

 I would like to print a string in the same format that I would 
 write it in the code (with quotes and with special characters 
 escaped). Similar to [Go's %q 
 format](https://pkg.go.dev/fmt#hdr-Printing). Is there a safe, 
 built-in way to do that?

 For example:

 ```
 string s = "one \"two\"\nthree four";
 writeln(/* ??? */);
 ```

 And get as output

 ```
 "one \"two\"\nthree four"
 ```

 Instead of

 ```
 one "two"
 three four
 ```


as a hack I always do:
```d
writeln([s]);
```
because arrays get serialized like D strings, there will be 
additional `[` and `]` though.

Sample output:
```
["Hello there \"uwu\" ``\x1B[Dabc\n"]
```
Jan 02 2022
parent reply Amit <a a.a> writes:
On Sunday, 2 January 2022 at 19:26:50 UTC, WebFreak001 wrote:

 as a hack I always do:
 ```d
 writeln([s]);
 ```
 because arrays get serialized like D strings, there will be 
 additional `[` and `]` though.

 Sample output:
 ```
 ["Hello there \"uwu\" ``\x1B[Dabc\n"]
 ```


On Sunday, 2 January 2022 at 19:37:38 UTC, JG wrote:

 Also a bit of a hack.

 ```
 import std.stdio : writeln;
 import std.format : format;


     void main()
     {
         string s = "one \"two\"\nthree four";
         writeln(format("%(%s%)",[s]));

 }
 ```


Yes! That's what I needed.

I wrapped it in a function like so:

```d
string quote(string s) {
     return format("%s", [s])[1 .. $ - 1];
}
unittest {
     assert(quote("one \"two\"\nthree four") == `"one 
\"two\"\nthree four"`);
}
```

Thanks for your responses ^_^
Jan 02 2022
parent reply Caten <catenhu gmail.com> writes:
On Sunday, 2 January 2022 at 21:16:55 UTC, Amit wrote:

 On Sunday, 2 January 2022 at 19:26:50 UTC, WebFreak001 wrote:

 [...]


 On Sunday, 2 January 2022 at 19:37:38 UTC, JG wrote:

 [...]


 Yes! That's what I needed.

 I wrapped it in a function like so:

 ```d
 string quote(string s) {
     return format("%s", [s])[1 .. $ - 1];
 }
 unittest {
     assert(quote("one \"two\"\nthree four") == `"one 
 \"two\"\nthree four"`);
 }
 ```

 Thanks for your responses ^_^


Hi, I also need a function to "unquote" string, like this:
```d
assert(unquote(`\n`)=="\n");
```
Is there a way to do that?
Mar 20 2022
next sibling parent Salih Dincer <salihdb hotmail.com> writes:
On Sunday, 20 March 2022 at 09:42:44 UTC, Caten wrote:

 On Sunday, 2 January 2022 at 21:16:55 UTC, Amit wrote:

 On Sunday, 2 January 2022 at 19:26:50 UTC, WebFreak001 wrote:

 [...]


 On Sunday, 2 January 2022 at 19:37:38 UTC, JG wrote:

 [...]


 Yes! That's what I needed.

 I wrapped it in a function like so:

 ```d
 string quote(string s) {
     return format("%s", [s])[1 .. $ - 1];
 }
 unittest {
     assert(quote("one \"two\"\nthree four") == `"one 
 \"two\"\nthree four"`);
 }
 ```

 Thanks for your responses ^_^


 Hi, I also need a function to "unquote" string, like this:
 ```d
 assert(unquote(`\n`)=="\n");
 ```
 Is there a way to do that?


```d
void main()
{
   import std.array : replace;

   auto q = `Hello,\n deneme`;
   auto p = "Hello,\n deneme";

   assert(q.replace("\\n", "\n") == p);
}
```

SDB 79
Mar 20 2022
prev sibling parent reply cc <cc nevernet.com> writes:
On Sunday, 20 March 2022 at 09:42:44 UTC, Caten wrote:

 Hi, I also need a function to "unquote" string, like this:
 ```d
 assert(unquote(`\n`)=="\n");
 ```
 Is there a way to do that?


I rolled my own for that recently:
```d
string dequote(string str)  safe pure {
	if (str.length < 2)
		return str;
	if ((str[0] == '"' || str[0] == '\'' || str[0] == '`') && 
str[$-1] == str[0]) {
		return str[1 .. $-1];
	}
	return str;
}
```
Mar 22 2022
parent cc <cc nevernet.com> writes:
On Tuesday, 22 March 2022 at 07:18:00 UTC, cc wrote:

 On Sunday, 20 March 2022 at 09:42:44 UTC, Caten wrote:

 Hi, I also need a function to "unquote" string, like this:
 ```d
 assert(unquote(`\n`)=="\n");
 ```
 Is there a way to do that?


 I rolled my own for that recently:
 ```d
 string dequote(string str)  safe pure {
 	if (str.length < 2)
 		return str;
 	if ((str[0] == '"' || str[0] == '\'' || str[0] == '`') && 
 str[$-1] == str[0]) {
 		return str[1 .. $-1];
 	}
 	return str;
 }
 ```


Oops, I misread what you were asking for.  Was thinking quotes 
like quotation marks, not backslashes.
Mar 22 2022
prev sibling parent JG <someone somewhere.com> writes:
On Sunday, 2 January 2022 at 17:27:53 UTC, Amit wrote:

 Hi!

 I would like to print a string in the same format that I would 
 write it in the code (with quotes and with special characters 
 escaped). Similar to [Go's %q 
 format](https://pkg.go.dev/fmt#hdr-Printing). Is there a safe, 
 built-in way to do that?

 For example:

 ```
 string s = "one \"two\"\nthree four";
 writeln(/* ??? */);
 ```

 And get as output

 ```
 "one \"two\"\nthree four"
 ```

 Instead of

 ```
 one "two"
 three four
 ```


Also a bit of a hack.

```
import std.stdio : writeln;
import std.format : format;


     void main()
     {
         string s = "one \"two\"\nthree four";
         writeln(format("%(%s%)",[s]));

}
```
Jan 02 2022