Struct std::string::StringStable [-] [+] [src]

pub struct String {
    // some fields omitted
}

A growable string stored as a UTF-8 encoded buffer.

Methods

impl String

fn new() -> String

Creates a new string buffer initialized with the empty string.

Examples

fn main() { let mut s = String::new(); }
let mut s = String::new();

fn with_capacity(capacity: usize) -> String

Creates a new string buffer with the given capacity. The string will be able to hold exactly capacity bytes without reallocating. If capacity is 0, the string will not allocate.

Examples

fn main() { let mut s = String::with_capacity(10); }
let mut s = String::with_capacity(10);

fn from_str(string: &str) -> String

Creates a new string buffer from the given string.

Examples

#![feature(collections, core)] fn main() { let s = String::from_str("hello"); assert_eq!(&s[..], "hello"); }
let s = String::from_str("hello");
assert_eq!(&s[..], "hello");

fn from_utf8(vec: Vec<u8>) -> Result<String, FromUtf8Error>

Returns the vector as a string buffer, if possible, taking care not to copy it.

Failure

If the given vector is not valid UTF-8, then the original vector and the corresponding error is returned.

Examples

#![feature(core)] extern crate std; fn main() { use std::str::Utf8Error; let hello_vec = vec![104, 101, 108, 108, 111]; let s = String::from_utf8(hello_vec).unwrap(); assert_eq!(s, "hello"); let invalid_vec = vec![240, 144, 128]; let s = String::from_utf8(invalid_vec).err().unwrap(); let err = s.utf8_error(); assert_eq!(s.into_bytes(), [240, 144, 128]); }
use std::str::Utf8Error;

let hello_vec = vec![104, 101, 108, 108, 111];
let s = String::from_utf8(hello_vec).unwrap();
assert_eq!(s, "hello");

let invalid_vec = vec![240, 144, 128];
let s = String::from_utf8(invalid_vec).err().unwrap();
let err = s.utf8_error();
assert_eq!(s.into_bytes(), [240, 144, 128]);

fn from_utf8_lossy(v: &'a [u8]) -> Cow<'a, str>

Converts a vector of bytes to a new UTF-8 string. Any invalid UTF-8 sequences are replaced with U+FFFD REPLACEMENT CHARACTER.

Examples

fn main() { let input = b"Hello \xF0\x90\x80World"; let output = String::from_utf8_lossy(input); assert_eq!(output, "Hello \u{FFFD}World"); }
let input = b"Hello \xF0\x90\x80World";
let output = String::from_utf8_lossy(input);
assert_eq!(output, "Hello \u{FFFD}World");

fn from_utf16(v: &[u16]) -> Result<String, FromUtf16Error>

Decode a UTF-16 encoded vector v into a String, returning None if v contains any invalid data.

Examples

fn main() { // 𝄞music let mut v = &mut [0xD834, 0xDD1E, 0x006d, 0x0075, 0x0073, 0x0069, 0x0063]; assert_eq!(String::from_utf16(v).unwrap(), "𝄞music".to_string()); // 𝄞mu<invalid>ic v[4] = 0xD800; assert!(String::from_utf16(v).is_err()); }
// 𝄞music
let mut v = &mut [0xD834, 0xDD1E, 0x006d, 0x0075,
                  0x0073, 0x0069, 0x0063];
assert_eq!(String::from_utf16(v).unwrap(),
           "𝄞music".to_string());

// 𝄞mu<invalid>ic
v[4] = 0xD800;
assert!(String::from_utf16(v).is_err());

fn from_utf16_lossy(v: &[u16]) -> String

Decode a UTF-16 encoded vector v into a string, replacing invalid data with the replacement character (U+FFFD).

Examples

fn main() { // 𝄞mus<invalid>ic<invalid> let v = &[0xD834, 0xDD1E, 0x006d, 0x0075, 0x0073, 0xDD1E, 0x0069, 0x0063, 0xD834]; assert_eq!(String::from_utf16_lossy(v), "𝄞mus\u{FFFD}ic\u{FFFD}".to_string()); }
// 𝄞mus<invalid>ic<invalid>
let v = &[0xD834, 0xDD1E, 0x006d, 0x0075,
          0x0073, 0xDD1E, 0x0069, 0x0063,
          0xD834];

assert_eq!(String::from_utf16_lossy(v),
           "𝄞mus\u{FFFD}ic\u{FFFD}".to_string());

unsafe fn from_raw_parts(buf: *mut u8, length: usize, capacity: usize) -> String

Creates a new String from a length, capacity, and pointer.

This is unsafe because:

  • We call Vec::from_raw_parts to get a Vec<u8>;
  • We assume that the Vec contains valid UTF-8.

unsafe fn from_utf8_unchecked(bytes: Vec<u8>) -> String

Converts a vector of bytes to a new String without checking if it contains valid UTF-8. This is unsafe because it assumes that the UTF-8-ness of the vector has already been validated.

fn into_bytes(self) -> Vec<u8>

Returns the underlying byte buffer, encoded as UTF-8.

Examples

#![feature(collections)] fn main() { let s = String::from_str("hello"); let bytes = s.into_bytes(); assert_eq!(bytes, [104, 101, 108, 108, 111]); }
let s = String::from_str("hello");
let bytes = s.into_bytes();
assert_eq!(bytes, [104, 101, 108, 108, 111]);

fn as_str(&self) -> &str

Extracts a string slice containing the entire string.

fn push_str(&mut self, string: &str)

Pushes the given string onto this string buffer.

Examples

#![feature(collections)] fn main() { let mut s = String::from_str("foo"); s.push_str("bar"); assert_eq!(s, "foobar"); }
let mut s = String::from_str("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(10); assert!(s.capacity() >= 10); }
let mut s = String::new();
s.reserve(10);
assert!(s.capacity() >= 10);

fn shrink_to_fit(&mut self)

Shrinks the capacity of this string buffer to match its length.

Examples

#![feature(collections)] fn main() { let mut s = String::from_str("foo"); s.reserve(100); assert!(s.capacity() >= 100); s.shrink_to_fit(); assert_eq!(s.capacity(), 3); }
let mut s = String::from_str("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

#![feature(collections)] fn main() { let mut s = String::from_str("abc"); s.push('1'); s.push('2'); s.push('3'); assert_eq!(s, "abc123"); }
let mut s = String::from_str("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

#![feature(collections)] fn main() { let s = String::from_str("hello"); let b: &[_] = &[104, 101, 108, 108, 111]; assert_eq!(s.as_bytes(), b); }
let s = String::from_str("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

#![feature(collections)] fn main() { let mut s = String::from_str("hello"); s.truncate(2); assert_eq!(s, "he"); }
let mut s = String::from_str("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

#![feature(collections)] fn main() { let mut s = String::from_str("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_str("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

#![feature(collections)] fn main() { let mut s = String::from_str("foo"); assert_eq!(s.remove(0), 'f'); assert_eq!(s.remove(1), 'o'); assert_eq!(s.remove(0), 'o'); }
let mut s = String::from_str("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

#![feature(collections)] fn main() { let mut s = String::from_str("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_str("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());

Trait Implementations

impl Borrow<str> for String

fn borrow(&self) -> &str

impl FromIterator<char> for String

fn from_iter<I>(iter: I) -> String where I: IntoIterator<Item=char>

impl<'a> FromIterator<&'a str> for String

fn from_iter<I>(iter: I) -> String where I: IntoIterator<Item=&'a str>

impl Extend<char> for String

fn extend<I>(&mut self, iterable: I) where I: IntoIterator<Item=char>

impl<'a> Extend<&'a str> for String

fn extend<I>(&mut self, iterable: I) where I: IntoIterator<Item=&'a str>

impl<'a, 'b> Pattern<'a> for &'b String

A convenience impl that delegates to the impl for &str

type Searcher = &'b str::Searcher

fn into_searcher(self, haystack: &'a str) -> &'b str::Searcher

fn is_contained_in(self, haystack: &'a str) -> bool

fn is_prefix_of(self, haystack: &'a str) -> bool

fn is_suffix_of(self, haystack: &'a str) -> bool where Self::Searcher: ReverseSearcher<'a>

impl PartialEq<String> for String

fn eq(&self, other: &String) -> bool

fn ne(&self, other: &String) -> bool

impl<'a> PartialEq<str> for String

fn eq(&self, other: &str) -> bool

fn ne(&self, other: &str) -> bool

impl<'a> PartialEq<&'a str> for String

fn eq(&self, other: &&'a str) -> bool

fn ne(&self, other: &&'a str) -> bool

impl<'a> PartialEq<Cow<'a, str>> for String

fn eq(&self, other: &Cow<'a, str>) -> bool

fn ne(&self, other: &Cow<'a, str>) -> bool

impl Default for String

fn default() -> String

impl Display for String

fn fmt(&self, f: &mut Formatter) -> Result<(), Error>

impl Debug for String

fn fmt(&self, f: &mut Formatter) -> Result<(), Error>

impl Hash for String

fn hash<H>(&self, hasher: &mut H) where H: Hasher

fn hash_slice<H>(data: &[Self], state: &mut H) where H: Hasher

impl<'a> Add<&'a str> for String

type Output = String

fn add(self, other: &str) -> String

impl Index<Range<usize>> for String

type Output = str

fn index(&self, index: Range<usize>) -> &str

impl Index<RangeTo<usize>> for String

type Output = str

fn index(&self, index: RangeTo<usize>) -> &str

impl Index<RangeFrom<usize>> for String

type Output = str

fn index(&self, index: RangeFrom<usize>) -> &str

impl Index<RangeFull> for String

type Output = str

fn index(&self, _index: RangeFull) -> &str

impl Deref for String

type Target = str

fn deref(&self) -> &str

impl FromStr for String

type Err = ParseError

fn from_str(s: &str) -> Result<String, ParseError>

impl AsRef<str> for String

fn as_ref(&self) -> &str

impl AsRef<[u8]> for String

fn as_ref(&self) -> &[u8]

impl<'a> From<&'a str> for String

fn from(s: &'a str) -> String

impl Into<Vec<u8>> for String

fn into(self) -> Vec<u8>

impl IntoCow<'static, str> for String

fn into_cow(self) -> Cow<'static, str>

impl Write for String

fn write_str(&mut self, s: &str) -> Result<(), Error>

fn write_fmt(&mut self, args: Arguments) -> Result<(), Error>

impl OwnedAsciiExt for String

fn into_ascii_uppercase(self) -> String

fn into_ascii_lowercase(self) -> String

impl AsRef<OsStr> for String

fn as_ref(&self) -> &OsStr

impl AsRef<Path> for String

fn as_ref(&self) -> &Path

Derived Implementations

impl Ord for String

fn cmp(&self, __arg_0: &String) -> Ordering

impl Eq for String

impl PartialOrd<String> for String

fn partial_cmp(&self, __arg_0: &String) -> Option<Ordering>

fn lt(&self, __arg_0: &String) -> bool

fn le(&self, __arg_0: &String) -> bool

fn gt(&self, __arg_0: &String) -> bool

fn ge(&self, __arg_0: &String) -> bool

impl Clone for String

fn clone(&self) -> String

fn clone_from(&mut self, source: &Self)