英文:
Conditional REGEX in R to select text in front of or behind a specific character --- "%" in this case
问题
ShippingStreet <- c("123 Main St%234 Center Street", "%555 Folsom Street",
"59 Hyde Street%")
我有一个地址的字符向量，它是通过合并两个不同向量的内容形成的。一个“%”分隔每个观察中的数据，左边（1）和右边（2）。数据看起来像这样：
我想保留“%”左边的数据，即使右边有内容，如果左边没有内容，我想保留右边的数据。
所以输出应该如下所示：
123 Main St
555 Folsom Street
59 Hyde Street
我编写了一个条件正则表达式如下，并在gsub中使用它，但它没有做我认为它应该做的事情。
pattrn_pct <- "/(?(?=%)..(%.*$)|(^.*%))/gm" <<< 寻找 %，然后选择 % 后面的内容，如果 % 前面有内容，则删除，或者如果 % 前面没有内容，则选择 % 后面的内容...gsub(pattrn_pct, "", ShippingStreet, perl = TRUE) <<< 用空字符串替换选择
请注意，你提供的正则表达式语法在R中可能不适用，你可以尝试以下代码来实现你的目标：
ShippingStreet <- c("123 Main St%234 Center Street", "%555 Folsom Street","59 Hyde Street%")# 使用正则表达式替换来提取所需的部分result <- gsub(".*?%([^%]+)|%.*$", "\", ShippingStreet)# 输出结果cat(result, sep = "\n")
这将输出所期望的结果。
英文:
I have a character vector of addresses which is formed by merging contents of two different vectors. A "%" separates the data in each observation, left(1) from right(2). And the data looks like this:
ShippingStreet <- c("123 Main St%234 Center Street", "%555 Folsom Street","59 Hyde Street%")
I want to keep the data on the left side of % even if there is something on the right, and on the right side if there is nothing on the left.
So output should look like this:
123 Main St555 Folsom Street59 Hyde street
I wrote a conditional regex as follows and use it in the gsub, but it is not doing what I though it should do.
pattrn_pct <- "/(?(?=%)..(%.*$)|(^.*%))/gm"` <<< looks for % and then selects behind the % to drop if there is something in front of the %, or after the % if nothing in front ...gsub(pattrn_pct, "", ShippingStreet, perl=T) <<< replace selection with ""
答案1
得分: 1
我们可以在这里使用str_extract()，使用正则表达式模式[^%]+：
str_extract(ShippingStreet, "[^%]+")
数据：
ShippingStreet <- c("123 Main St%234 Center Street", "%555 Folsom Street","59 Hyde Street%")
英文:
We can use str_extract() here with the regex pattern [^%]+:
str_extract(ShippingStreet, "[^%]+")[1] "123 Main St" "555 Folsom Street" "59 Hyde Street"
Data:
ShippingStreet <- c("123 Main St%234 Center Street", "%555 Folsom Street","59 Hyde Street%")
答案2
得分: 0
使用base R中的sub
sub("^%?([^%]+).*", "\", ShippingStreet)[1] "123 Main St" "555 Folsom Street" "59 Hyde Street"
英文:
Using sub in base R
sub("^%?([^%]+).*", "\", ShippingStreet)[1] "123 Main St" "555 Folsom Street" "59 Hyde Street"</details>
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