mirror of
https://github.com/jbranchaud/til
synced 2026-01-03 15:18:01 +00:00
45 lines
937 B
Markdown
45 lines
937 B
Markdown
# Referencing Values In IEx's History
|
|
|
|
Each time we execute a statement in an `iex` session, the counter is
|
|
incremented. These numbers are references to the history of the session. We
|
|
can use these references to _refer_ to previously executed values using
|
|
`v/1`. This is particularly handy for multi-line statements or when we
|
|
forget to bind to the result of some function.
|
|
|
|
Consider the following `iex` session:
|
|
|
|
```elixir
|
|
iex(1)> :one
|
|
:one
|
|
iex(2)> 1 + 1
|
|
2
|
|
iex(3)> "three" |> String.to_atom()
|
|
:three
|
|
```
|
|
|
|
If we execute `v()` on its own, it is the same as `v(-1)` in that it will
|
|
give us the latest value in the history.
|
|
|
|
```elixir
|
|
iex(4)> v()
|
|
:three
|
|
```
|
|
|
|
Providing any positive number will refer to the references we see next to
|
|
each statement.
|
|
|
|
```elixir
|
|
iex(5)> v(1)
|
|
:one
|
|
```
|
|
|
|
Negative numbers, as we saw with `v(-1)`, will count backwards in the
|
|
history from where we are.
|
|
|
|
```elixir
|
|
iex(6)> v(-4)
|
|
2
|
|
```
|
|
|
|
See `h v` for more details.
|