stt1571-2023-act02-lucaser-sheilamae-ch-04.qmd

---
title: "Chapter 04: Filtering rows"
author: "Sheila Mae Lucaser"
format: html
editor: visual
---

## 4.1 Row-position selection

```{r}
iris %>% 
  slice(1:5)
```

```{r}
iris %>% 
  slice(-(1:floor(n()/3)))
```

## 4.2 Conditional selection

```{r}
iris %>% 
  filter(Species=="virginica")
```

```{r}
iris %>% 
  filter(Species == "virginica",
         Sepal.Length > mean(Sepal.Length))
```

```{r}
iris %>% 
  filter(Species == "virginica" |
           Sepal.Length > mean(Sepal.Length))
```

## 4.3 Advanced row filtering

```{r}
iris %>% 
  filter_all(any_vars(.>7.5))
```

```{r}
iris %>% 
  filter_all(any_vars(abs(. - mean(.))>2*sd(.)))
```

```{r}
iris %>% 
  filter_all(all_vars(. < mean(.)))
```

```{r}
iris %>% 
  filter_if(is.numeric, all_vars(.<mean(.)))
```

```{r}
iris %>% 
  filter_if(~is.numeric(.) & n_distinct(.)>30,
            any_vars(.<mean(.)))
```

```{r}
iris %>% 
  filter_at(vars(ends_with("Length")),
            all_vars(.<mean(.)))
```

## 4.4 Summary

## 4.5 Exercises