去掉单词右边至少2个空格的所有数字和逗号

Question

我正在尝试抓取这个支持微软语音服务的区域表。我设法得到以下字符向量：

region <- c("southafricanorth 6", "eastasia 5", "southeastasia 1,2,3,4,5", 
"australiaeast 1,2,3,4", "centralindia 1,2,3,4,5", "japaneast 2,5", 
"japanwest", "koreacentral 2", "canadacentral 1", "northeurope 1,2,4,5", 
"westeurope 1,2,3,4,5", "francecentral", "germanywestcentral", 
"norwayeast", "switzerlandnorth 6", "switzerlandwest", "uksouth 1,2,3,4", 
"uaenorth 6", "brazilsouth 6", "centralus", "eastus 1,2,3,4,5", 
"eastus2 1,2,4,5", "northcentralus 4,6", "southcentralus 1,2,3,4,5,6", 
"westcentralus 5", "westus 2,5", "westus2 1,2,4,5", "westus3"
)

去掉单词右边至少 2 个空格的所有数字和逗号的正则表达式是什么？例如，我只想要

westus2

，而不是

westus2 1,2,4,5

。

我试过这个无济于事：

gsub("\\s{2,}\\d+.*", "", region)

Answer 1

没有上标的区域名称包含在 HTML 中的

<code>

标签内。因此，您可以通过将抓取代码修改为类似以下内容来避免使用正则表达式：

library(rvest)

url <- "https://learn.microsoft.com/en-us/azure/cognitive-services/Speech-Service/regions"

regions <- read_html(url) %>% 
  # first table only
  html_element("table") %>% 
  html_elements("code") %>% 
  html_text()

regions

[1] "southafricanorth"   "eastasia"           "southeastasia"      "australiaeast"      
    "centralindia"       "japaneast"          "japanwest"          "koreacentral"      
[9] "canadacentral"      "northeurope"        "westeurope"         "francecentral"      
    "germanywestcentral" "norwayeast"         "switzerlandnorth"   "switzerlandwest"   
[17] "uksouth"            "uaenorth"           "brazilsouth"        "centralus"          
     "eastus"             "eastus2"            "northcentralus"     "southcentralus"    
[25] "westcentralus"      "westus"             "westus2"            "westus3"

Answer 2

另一个优雅的解决方案是

word()

包中的

stringr

函数：

默认第一个字：

word(string, start = 1L, end = start, sep = fixed(" "))

library(stringr)

word(region)

 [1] "southafricanorth"   "eastasia"           "southeastasia"      "australiaeast"     
 [5] "centralindia"       "japaneast"          "japanwest"          "koreacentral"      
 [9] "canadacentral"      "northeurope"        "westeurope"         "francecentral"     
[13] "germanywestcentral" "norwayeast"         "switzerlandnorth"   "switzerlandwest"   
[17] "uksouth"            "uaenorth"           "brazilsouth"        "centralus"         
[21] "eastus"             "eastus2"            "northcentralus"     "southcentralus"    
[25] "westcentralus"      "westus"             "westus2"            "westus3"