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RUST String Methods - String Object

Below table show the common string methods supported by RUST

Method Signature Description
new() pub const fn new() -> String Creates a new empty String.
to_string() fn to_string(&self) -> String  Converts the given value to a String.
replace()  pub fn replace<'a, P>(&'a self, from: P, to: &str) -> String Replaces all matches of a pattern with another string. 
as_str()  pub fn as_str(&self) -> &str Extracts a string slice containing the entire string. 
push() pub fn push(&mut self, ch: char)  Appends the given char to the end of this String.
push_str()  pub fn push_str(&mut self, string: &str)  Appends a given string slice onto the end of this String.
len() pub fn len(&self) -> usize  Returns the length of this String, in bytes.
trim() pub fn trim(&self) -> &str Returns a string slice with leading and trailing whitespace removed.
split_whitespa ce()  pub fn split_whitespace(&self) - > SplitWhitespace Splits a string slice by whitespace and returns an iterator.
split() pub fn split<'a, P>(&'a self, pat: P) -> Split<'a, P> , where P is pattern can be &str, char, or a closure that determines the split. Returns an iterator over substrings of this string slice, separated by characters matched by a pattern.
chars() pub fn chars(&self) -> Chars Returns an iterator over the chars of a string slice.

new() Example

An empty string object is created using the new() method and its value is set to hello.

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



to_string() Example

To access all methods of String object, convert a string literal to object type using the to_string() function.

fn main(){
 let full_Name = "Jhon Smith".to_string();
 println!("{}",full_Name );


Jhon Smith

replace() Example

The replace() function takes two parameters – the first parameter is a string pattern to search for and the second parameter is the new value to be replaced.

fn main(){
 let hellowWorld = "Hello World";
 let helloPeter= hellowWorld .replace("World","Peter");


Hello Peter

as_str() Example

The as_str() function extracts a string slice containing the entire string.

fn main(){
 let first_Name= String::from("Jhon");
 let first_Name_As_String= first_Name.as_str();
 println!("First Name As String {}",first_Name_As_String);



First Name As String Jhon

push() Example

The push() function appends the given char to the end of this String.

fn main(){
 let books= String::from("My book");



My books

push_str() Example

The push_str() function appends a given string slice onto the end of a String.

fn main(){
 let book= String::from("My book");
 book.push_str(' is completed.');



My book is completed.

len() Example

The len() function returns the total number of characters in a string (including spaces).

fn main(){
 let fullname = "Jhon Smith";
 println!("length is {}",fullname.len());


length is 10

trim() Example

The trim() function removes leading and trailing spaces in a string. NOTE that this function will not remove the inline spaces.

fn main(){
 let fullname = "       Jhon Smith   ";
 println!("length is {}",fullname.trim().len());


length is 10

split_whitespace() Example

The split_whitespace() splits the input string into different strings.

fn main(){
 let msg = "Car Bus Bike Boat".to_string();
 for token in msg.split_whitespace(){
 println!("Word: {}",token);


Word: Car
Word: Bus
Word: Bike
Word: Boat

split() Example

The split() string method returns an iterator over substrings of a string slice, separated by characters matched by a pattern. The limitation of the split() method is that the result cannot be stored for later use. The collect method can be used to store the result returned by split() as a vector.

Example might be hard to understand now, it's better to understand RUST Array First.

fn main(){
 let fullname = "Jhon,William,Charles";

 for token in fullname.split(","){
  println!("Name is {}",token);


Name is Jhon
Name is William
Name is Charles

chars() Example

Individual characters in a string can be accessed using the chars method.

fn main(){
 let word = "Mock".to_string();
 for char_in_word in word.chars(){




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