How do I split a string in Rust

Question

From the documentation  it s not clear  In Java you could use the split method like so    some string 123 ffd  split  123

User · Answer

There is a special method split for struct String   fn split lt  a  P gt   amp  a self  pat  P  - gt  Split lt  a  P gt  where P  Pattern lt  a gt    Split by char   let v  Vec lt  amp str gt     Mary had a little lamb  split      collect    assert eq  v    Mary    had    a    little    lamb       Split by string   let v  Vec lt  amp str gt     lion  tiger  leopard  split       collect    assert eq  v    lion    tiger    leopard       Split by closure   let v  Vec lt  amp str gt     abc1def2ghi  split  c  char  c is numeric    collect    assert eq  v    abc    def    ghi

User · Answer

There are three simple ways   By separator   s split  quot separator quot       s split          s split char  is numeric    By whitespace   s split whitespace     By newlines   s lines     By regex   using regex crate   Regex  new r quot  s quot   unwrap   split  quot one two three quot      The result of each kind is an iterator  let text    quot foo r nbar n nbaz n quot   let mut lines   text lines     assert eq  Some  quot foo quot    lines next     assert eq  Some  quot bar quot    lines next     assert eq  Some  quot  quot    lines next     assert eq  Some  quot baz quot    lines next      assert eq  None  lines next

User · Answer

Use split    let mut split    some string 123 ffd  split  123      This gives an iterator  which you can loop over  or collect   into a vector   for s in split       println        s    let vec   split collect   lt Vec lt  amp str gt  gt        OR let vec  Vec lt  amp str gt    split collect

User · Answer

There s also split whitespace    fn main         let words  Vec lt  amp str gt        foo   bar t nbaz     split whitespace   collect        println          words            foo    bar    baz

User · Answer

split returns an Iterator  which you can convert into a Vec using collect  split line collect   lt Vec lt   gt  gt     Going through an iterator instead of returning a Vec directly has several advantages    split is lazy  This means that it won t really split the line until you need it  That way it won t waste time splitting the whole string if you only need the first few values  split line take 2  collect   lt Vec lt   gt  gt     or even if you need only the first value that can be converted to an integer  split line filter map  x  x parse   lt i32 gt    ok    next    This last example won t waste time attempting to process the  23 0  but will stop processing immediately once it finds the  1   split makes no assumption on the way you want to store the result  You can use a Vec  but you can also use anything that implements FromIterator lt  amp str gt   for example a LinkedList or a VecDeque  or any custom type that implements FromIterator lt  amp str gt

[rust] How do I split a string in Rust?

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