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/// Inserts an element at position `index` within the vector.
///
///
/// # Arguments
///
/// * `vec` - The vector to insert.
///
/// * `index` - The position of vector to insert at.
///
/// * `item` - The element to be inserted.
///
/// # Returns
///
/// Result true return if insert successed, error if if insert failed.
///
/// # Examples
///
/// ```
/// use rufl::collection;
///
/// let mut vec = vec!["a", "b", "c"];
///
/// let result = collection::insert_at(&mut vec, 3, "d");
///
/// assert_eq!(true, result.ok().unwrap());
/// assert_eq!(vec!["a", "b", "c", "d"], vec);
///
/// ```
pub fn insert_at<T>(vec: &mut Vec<T>, index: usize, item: T) -> Result<bool, String> {
if index > vec.len() {
return Err(String::from("insert_at: index should be <= vecor length"));
}
vec.insert(index, item);
Ok(true)
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_insert_at() {
let mut vec = vec![];
let result = insert_at(&mut vec, 0, "a");
assert_eq!(true, result.ok().unwrap());
assert_eq!(vec!["a"], vec);
let result = insert_at(&mut vec, 1, "b");
assert_eq!(true, result.ok().unwrap());
assert_eq!(vec!["a", "b"], vec);
let result = insert_at(&mut vec, 3, "c");
assert_eq!(
"insert_at: index should be <= vecor length",
result.err().unwrap()
);
assert_eq!(vec!["a", "b"], vec);
}
}