借助辅助函数
使用 dplyr 编程
Dr. Chester Ismay
Educator, Data Scientist, and R/Python Consultant
starts_with()
- 与
select()搭配时，查找以给定子串开头的列名 - 属于
tidyselect包，但运行library(dplyr)时会自动加载
starts_with() 示例
world_bank_data %>%
select(starts_with("perc"))
# A tibble: 300 x 4
perc_electric_access perc_college_complete perc_cvd_crd_70 perc_rural_pop
<dbl> <dbl> <dbl> <dbl>
1 100 7.26 15.8 45.6
2 100 20.4 26.2 35.6
3 100 18.0 28.1 30.8
4 100 7.57 15.5 45.0
5 83.8 3.92 33.3 66.0
# ... with 295 more rows
这些结果来自何地与何时？
world_bank_data %>%
select(country, year, starts_with("perc"))
# A tibble: 300 x 6
country year perc_electric_access perc_college_complete perc_cvd_crd_70 perc_rural_pop
<chr> <dbl> <dbl> <dbl> <dbl> <dbl>
1 Portugal 2000 100 7.26 15.8 45.6
2 Armenia 2001 100 20.4 26.2 35.6
3 Bulgaria 2001 100 18.0 28.1 30.8
4 Portugal 2001 100 7.57 15.5 45.0
5 Pakistan 2005 83.8 3.92 33.3 66.0
# ... with 295 more rows
ends_with()
world_bank_data %>%
select(country, year, ends_with("rate"))
# A tibble: 300 x 5
country year infant_mortality_rate fertility_rate unemployment_rate
<chr> <dbl> <dbl> <dbl> <dbl>
1 Portugal 2000 5.5 1.47 3.81
2 Armenia 2001 25.3 1.2 10.9
3 Bulgaria 2001 17.1 1.2 19.9
4 Portugal 2001 5.2 1.46 3.83
5 Pakistan 2005 80 3.79 0.610
# ... with 295 more rows
让我们来练习！
使用 dplyr 编程
