Struct std::string::DerefString
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[src]
pub struct DerefString<'a> {
// some fields omitted
}Wrapper type providing a &String reference via Deref.
Methods from Deref<Target=String>
fn into_bytes(self) -> Vec<u8>
Returns the underlying byte buffer, encoded as UTF-8.
Examples
fn main() { let s = String::from("hello"); let bytes = s.into_bytes(); assert_eq!(bytes, [104, 101, 108, 108, 111]); }let s = String::from("hello"); let bytes = s.into_bytes(); assert_eq!(bytes, [104, 101, 108, 108, 111]);
fn as_str(&self) -> &str
: waiting on RFC revision
Extracts a string slice containing the entire string.
fn push_str(&mut self, string: &str)
Pushes the given string onto this string buffer.
Examples
fn main() { let mut s = String::from("foo"); s.push_str("bar"); assert_eq!(s, "foobar"); }let mut s = String::from("foo"); s.push_str("bar"); assert_eq!(s, "foobar");
fn capacity(&self) -> usize
Returns the number of bytes that this string buffer can hold without reallocating.
Examples
fn main() { let s = String::with_capacity(10); assert!(s.capacity() >= 10); }let s = String::with_capacity(10); assert!(s.capacity() >= 10);
fn reserve(&mut self, additional: usize)
Reserves capacity for at least additional more bytes to be inserted
in the given String. The collection may reserve more space to avoid
frequent reallocations.
Panics
Panics if the new capacity overflows usize.
Examples
fn main() { let mut s = String::new(); s.reserve(10); assert!(s.capacity() >= 10); }let mut s = String::new(); s.reserve(10); assert!(s.capacity() >= 10);
fn reserve_exact(&mut self, additional: usize)
Reserves the minimum capacity for exactly additional more bytes to be
inserted in the given String. Does nothing if the capacity is already
sufficient.
Note that the allocator may give the collection more space than it
requests. Therefore capacity can not be relied upon to be precisely
minimal. Prefer reserve if future insertions are expected.
Panics
Panics if the new capacity overflows usize.
Examples
fn main() { let mut s = String::new(); s.reserve_exact(10); assert!(s.capacity() >= 10); }let mut s = String::new(); s.reserve_exact(10); assert!(s.capacity() >= 10);
fn shrink_to_fit(&mut self)
Shrinks the capacity of this string buffer to match its length.
Examples
fn main() { let mut s = String::from("foo"); s.reserve(100); assert!(s.capacity() >= 100); s.shrink_to_fit(); assert_eq!(s.capacity(), 3); }let mut s = String::from("foo"); s.reserve(100); assert!(s.capacity() >= 100); s.shrink_to_fit(); assert_eq!(s.capacity(), 3);
fn push(&mut self, ch: char)
Adds the given character to the end of the string.
Examples
fn main() { let mut s = String::from("abc"); s.push('1'); s.push('2'); s.push('3'); assert_eq!(s, "abc123"); }let mut s = String::from("abc"); s.push('1'); s.push('2'); s.push('3'); assert_eq!(s, "abc123");
fn as_bytes(&self) -> &[u8]
Works with the underlying buffer as a byte slice.
Examples
fn main() { let s = String::from("hello"); let b: &[_] = &[104, 101, 108, 108, 111]; assert_eq!(s.as_bytes(), b); }let s = String::from("hello"); let b: &[_] = &[104, 101, 108, 108, 111]; assert_eq!(s.as_bytes(), b);
fn truncate(&mut self, new_len: usize)
Shortens a string to the specified length.
Panics
Panics if new_len > current length,
or if new_len is not a character boundary.
Examples
fn main() { let mut s = String::from("hello"); s.truncate(2); assert_eq!(s, "he"); }let mut s = String::from("hello"); s.truncate(2); assert_eq!(s, "he");
fn pop(&mut self) -> Option<char>
Removes the last character from the string buffer and returns it.
Returns None if this string buffer is empty.
Examples
fn main() { let mut s = String::from("foo"); assert_eq!(s.pop(), Some('o')); assert_eq!(s.pop(), Some('o')); assert_eq!(s.pop(), Some('f')); assert_eq!(s.pop(), None); }let mut s = String::from("foo"); assert_eq!(s.pop(), Some('o')); assert_eq!(s.pop(), Some('o')); assert_eq!(s.pop(), Some('f')); assert_eq!(s.pop(), None);
fn remove(&mut self, idx: usize) -> char
Removes the character from the string buffer at byte position idx and
returns it.
Warning
This is an O(n) operation as it requires copying every element in the buffer.
Panics
If idx does not lie on a character boundary, or if it is out of
bounds, then this function will panic.
Examples
fn main() { let mut s = String::from("foo"); assert_eq!(s.remove(0), 'f'); assert_eq!(s.remove(1), 'o'); assert_eq!(s.remove(0), 'o'); }let mut s = String::from("foo"); assert_eq!(s.remove(0), 'f'); assert_eq!(s.remove(1), 'o'); assert_eq!(s.remove(0), 'o');
fn insert(&mut self, idx: usize, ch: char)
Inserts a character into the string buffer at byte position idx.
Warning
This is an O(n) operation as it requires copying every element in the buffer.
Panics
If idx does not lie on a character boundary or is out of bounds, then
this function will panic.
unsafe fn as_mut_vec(&mut self) -> &mut Vec<u8>
Views the string buffer as a mutable sequence of bytes.
This is unsafe because it does not check to ensure that the resulting string will be valid UTF-8.
Examples
fn main() { let mut s = String::from("hello"); unsafe { let vec = s.as_mut_vec(); assert!(vec == &[104, 101, 108, 108, 111]); vec.reverse(); } assert_eq!(s, "olleh"); }let mut s = String::from("hello"); unsafe { let vec = s.as_mut_vec(); assert!(vec == &[104, 101, 108, 108, 111]); vec.reverse(); } assert_eq!(s, "olleh");
fn len(&self) -> usize
Returns the number of bytes in this string.
Examples
fn main() { let a = "foo".to_string(); assert_eq!(a.len(), 3); }let a = "foo".to_string(); assert_eq!(a.len(), 3);
fn is_empty(&self) -> bool
Returns true if the string contains no bytes
Examples
fn main() { let mut v = String::new(); assert!(v.is_empty()); v.push('a'); assert!(!v.is_empty()); }let mut v = String::new(); assert!(v.is_empty()); v.push('a'); assert!(!v.is_empty());
fn clear(&mut self)
Truncates the string, returning it to 0 length.
Examples
fn main() { let mut s = "foo".to_string(); s.clear(); assert!(s.is_empty()); }let mut s = "foo".to_string(); s.clear(); assert!(s.is_empty());
fn drain<R>(&mut self, range: R) -> Drain where R: RangeArgument<usize>
: recently added, matches RFC
Create a draining iterator that removes the specified range in the string and yields the removed chars from start to end. The element range is removed even if the iterator is not consumed until the end.
Panics
Panics if the starting point or end point are not on character boundaries, or if they are out of bounds.
Examples
#![feature(collections_drain)] fn main() { let mut s = String::from("α is alpha, β is beta"); let beta_offset = s.find('β').unwrap_or(s.len()); // Remove the range up until the β from the string let t: String = s.drain(..beta_offset).collect(); assert_eq!(t, "α is alpha, "); assert_eq!(s, "β is beta"); // A full range clears the string s.drain(..); assert_eq!(s, ""); }let mut s = String::from("α is alpha, β is beta"); let beta_offset = s.find('β').unwrap_or(s.len()); // Remove the range up until the β from the string let t: String = s.drain(..beta_offset).collect(); assert_eq!(t, "α is alpha, "); assert_eq!(s, "β is beta"); // A full range clears the string s.drain(..); assert_eq!(s, "");