---
title: "代码编写规则"
subtitle: 《区域水环境污染数据分析实践》<br>Data analysis practice of regional water environment pollution
author: 苏命、王为东<br>中国科学院大学资源与环境学院<br>中国科学院生态环境研究中心
date: today
lang: zh
format:
  revealjs:
    theme: dark
    slide-number: true
    chalkboard:
      buttons: true
    preview-links: auto
    lang: zh
    toc: true
    toc-depth: 1
    toc-title: 大纲
    logo: ./_extensions/inst/img/ucaslogo.png
    css: ./_extensions/inst/css/revealjs.css
    pointer:
      key: "p"
      color: "#32cd32"
      pointerSize: 18
revealjs-plugins:
  - pointer
filters:
  - d2
---


```{r}
#| echo: false
knitr::opts_chunk$set(echo = TRUE)
source("../../coding/_common.R")
library(tidyverse)
library(nycflights13)
```

## 代码编写规则

```{r}
#| eval: false

# Strive for:
short_flights <- flights |> filter(air_time < 60)

# Avoid:
SHORTFLIGHTS <- flights |> filter(air_time < 60)

# Strive for
z <- (a + b)^2 / d

# Avoid
z<-( a + b ) ^ 2/d

# Strive for
mean(x, na.rm = TRUE)

# Avoid
mean (x ,na.rm=TRUE)
```

## 练习

```{r}
flights|>filter(dest=="IAH")|>group_by(year,month,day)|>summarize(n=n(),
delay=mean(arr_delay,na.rm=TRUE))|>filter(n>10)

flights|>filter(carrier=="UA",dest%in%c("IAH","HOU"),sched_dep_time>
0900,sched_arr_time<2000)|>group_by(flight)|>summarize(delay=mean(
arr_delay,na.rm=TRUE),cancelled=sum(is.na(arr_delay)),n=n())|>filter(n>10)
```





## 欢迎讨论！{.center}


`r rmdify::slideend(wechat = FALSE, type = "public", tel = FALSE, thislink = "https://drwater.rcees.ac.cn/course/public/RWEP/@PUB/SD/")`

