Function std.format.read.formattedRead
Reads an input range according to a format string and stores the read values into its arguments.
uint formattedRead(Range, Char, Args...)
(
auto ref Range r,
const(Char)[] fmt,
auto ref Args args
);
uint formattedRead(alias fmt, Range, Args...)
(
auto ref Range r,
auto ref Args args
)
if (isSomeString!(typeof(fmt)));
Format specifiers with format character 'd', 'u' and 'c' can take a '*' parameter for skipping values.
The second version of formattedRead takes the format string as
template argument. In this case, it is checked for consistency at
compile-time.
Parameters
| Name | Description |
|---|---|
| r | an input range, where the formatted input is read from |
| fmt | a format string |
| args | a variadic list of arguments where the read values are stored |
| Range | the type of the input range r |
| Char | the character type used for fmt |
| Args | a variadic list of types of the arguments |
Returns
The number of variables filled. If the input range r ends early,
this number will be less than the number of variables provided.
Throws
A FormatException if reading did not succeed.
Note
For backward compatibility the arguments args can be given as pointers
to that variable, but it is not recommended to do so, because this
option might be removed in the future.
Example
string object;
char cmp;
int value;
writeln(formattedRead("angle < 36", "%s %c %d", object, cmp, value)); // 3
writeln(object); // "angle"
writeln(cmp); // '<'
writeln(value); // 36
// reading may end early:
writeln(formattedRead("length >", "%s %c %d", object, cmp, value)); // 2
writeln(object); // "length"
writeln(cmp); // '>'
// value is not changed:
writeln(value); // 36
Example
The format string can be checked at compile-time:
string a;
int b;
double c;
writeln("hello!124:34.5"Example
Skipping values
string item;
double amount;
writeln("orange: (12%) 15.25"Authors
Walter Bright, Andrei Alexandrescu, and Kenji Hara