根据R中特定字符的相对位置从字符串中删除字符

How to remove all characters before "p", and "p" itself, in all strings of v1 as in data frame below.

如何在v1的所有字符串中删除“p”和“p”本身之前的所有字符,如下面的数据框中所示。

df1 <- data.frame(v1 = c("m0p1", "m5p30", "m11p20", "m59p60"))

How to remove all characters after "p" and "p" itself? Thank you

如何删除“p”和“p”后面的所有字符?谢谢

3 个解决方案

#1

You could also do

你也可以这样做

sub('^[^p]*p', '', df1$v1)
#[1] "1"  "30" "20" "60"

sub('p.*$', '', df1$v1)
#[1] "m0"  "m5"  "m11" "m59"

#2

You can use gsub

你可以使用gsub

# Remove everything before p
gsub("^.*?p(.*)","\\1",df1$v1,perl=TRUE)
#[1] "1"  "30" "20" "60"

# Remove everything after p
gsub("(.*)?p.*$","\\1",df1$v1,perl=TRUE)
# [1] "m0"  "m5"  "m11" "m59"

#3

After p:

gsub('.*(?<=p)(\\d+)','\\1',df1$v1,perl=T)

Before p:

gsub('(.*)(?=p).*','\\1',df1$v1,perl=T)

#1