# `filter` keeps what clears your bar.

`filter` is a grep that reads. It keeps each record where the answer is yes and passes it through unchanged.

## Run it

*At 0.7, seven songs stay.*

```
is_a_song="The text is the title of a song by the Beatles."
on_abbey_road="It appears on the album Abbey Road."
question="$is_a_song $on_abbey_road"

cat <<'EOF' |
Octopus's Garden
Yellow Submarine
Something
Here Comes the Sun
Yesterday
Come Together
Hey Jude
Penny Lane
A Day in the Life
Her Majesty
Let It Be
Maxwell's Silver Hammer
EOF
thinkthen filter "$question" \
  --batch 1 \
  --threshold 0.7 \
  --replay recording
```

*Output*

```
Octopus's Garden
Something
Here Comes the Sun
Come Together
A Day in the Life
Her Majesty
Maxwell's Silver Hammer
```

*exit 0: the run finished*

## Change the bar

*At 0.9, five songs stay.*

```
is_a_song="The text is the title of a song by the Beatles."
on_abbey_road="It appears on the album Abbey Road."
question="$is_a_song $on_abbey_road"

cat <<'EOF' |
Octopus's Garden
Yellow Submarine
Something
Here Comes the Sun
Yesterday
Come Together
Hey Jude
Penny Lane
A Day in the Life
Her Majesty
Let It Be
Maxwell's Silver Hammer
EOF
thinkthen filter "$question" \
  --batch 1 \
  --threshold 0.9 \
  --replay recording
```

*Output*

```
Here Comes the Sun
Come Together
A Day in the Life
Her Majesty
Maxwell's Silver Hammer
```

*exit 0: the run finished*

## The lesson

Six of the seven songs at 0.7 are on Abbey Road. A Day in the Life came out on Sgt. Pepper's Lonely Hearts Club Band. At 0.9, Octopus's Garden and Something drop out. A Day in the Life stays.

A higher bar cannot remove a mistake Jev is sure of.

On GitHub: [github.com/botassembly/beatles-bench/tree/main/examples/filter](https://github.com/botassembly/beatles-bench/tree/main/examples/filter)