使用 R 在第一次出现整数时拆分字符串

Question

注意我已经读过 Split string at first occurrence of an integer in a string 但是我的要求不同，因为我想使用 R.

假设我有以下示例数据框：

> df = data.frame(name_and_address =
      c("Mr. Smith12 Some street",
        "Mr. Jones345 Another street",
        "Mr. Anderson6 A different street"))
> df
                  name_and_address
1          Mr. Smith12 Some street
2      Mr. Jones345 Another street
3 Mr. Anderson6 A different street

我想在第一次出现整数时拆分字符串。请注意，整数的长度不同。

所需的输出可以如下所示：

[[1]]
[1] "Mr. Smith"
[2] "12 Some street",

[[2]]
[1] "Mr. Jones"
[2] "345 Another street",

[[3]]
[1] "Mr. Anderson"
[2] "6 A different street"

我尝试了以下方法，但无法正确获取正则表达式：

# Attempt 1 (Does not work)
library(data.table)
tstrsplit(df,'(?=\d+)', perl=TRUE, type.convert=TRUE)

# Attempt 2 (Does not work)
library(stringr)
str_split(df, "\d+")

Answer 1

您可以使用 tidyr::extract:

library(tidyr)
df <- df %>% 
    extract("name_and_address", c("name", "address"), "(\D*)(\d.*)")
## => df
##           name              address
## 1    Mr. Smith       12 Some street
## 2    Mr. Jones   345 Another street
## 3 Mr. Anderson 6 A different street

(\D*)(\d.*) 正则表达式匹配以下内容：

(\D*) - 第 1 组：任意零个或多个 non-digit 个字符
(\d.*) - 第 2 组：一个数字，然后尽可能多的任意零个或多个字符。

另一种 stringr::str_split 的解决方案也是可能的：

str_split(df$name_and_address, "(?=\d)", n=2)
## => [[1]]
## [1] "Mr. Smith"      "12 Some street"

## [[2]]
## [1] "Mr. Jones"          "345 Another street"

## [[3]]
## [1] "Mr. Anderson"         "6 A different street"

(?=\d) 正向先行查找数字之前的位置，并且 n=2 告诉 stringr::str_split 最多只分成 2 个块。

如果字符串中没有数字，则不会 return 任何内容的基本 R 方法：

df = data.frame(name_and_address = c("Mr. Smith12 Some street", "Mr. Jones345 Another street", "Mr. Anderson6 A different street", "1 digit is at the start", "No digits, sorry."))

df$name <- sub("^(?:(\D*)\d.*|.+)", "\1", df$name_and_address)
df$address <- sub("^\D*(\d.*)?", "\1", df$name_and_address)
df$name
# => [1] "Mr. Smith"    "Mr. Jones"    "Mr. Anderson" ""             ""
df$address
# => [1] "12 Some street"          "345 Another street"     
#    [3] "6 A different street"    "1 digit is at the start"         ""

参见an online R demo。这也支持第一个数字是字符串中第一个字符的情况。

Answer 2

我会在这里使用 sub：

df$name <- sub("(\D+).*", "\1", df$name_and_address)
df$address <- sub(".*?(\d+.*)", "\1", df$name_and_address)

使用 R 在第一次出现整数时拆分字符串

Split String at First Occurrence of an Integer using R

regex

string

split

r

data.table