[英]How to change values before text in string using R
I have multiple strings that are similar to the following pattern:我有多个类似于以下模式的字符串:
dat<-("00000000AAAAAAAAAA0AAAAAAAAAA0AAAAAAAAAAAAAAAAAAAAAAAAD0")
I need to change all 0 values to "."我需要将所有 0 值更改为“。” before the first character value within a string.
在字符串中的第一个字符值之前。 My desired output in this example would be:
在此示例中,我想要的 output 将是:
"........AAAAAAAAAA0AAAAAAAAAA0AAAAAAAAAAAAAAAAAAAAAAAAD0". “........AAAAAAAAAA0AAAAAAAAAA0AAAAAAAAAAAAAAAAAAAAAAAAD0”。
I tried using gsub to accomplish this task:我尝试使用 gsub 来完成此任务:
gsub("\\G([^_\\d]*)\\d", ".\\1", dat, perl=T)
Unfortunately it changed all of the 0s to "."不幸的是,它把所有的 0 都改成了“.”。 instead of the 0s preceding the first "A".
而不是第一个“A”之前的 0。
Can someone please help me with this issue?有人可以帮我解决这个问题吗?
If you wish to simply replace each leading 0
with a .
如果您想简单地将每个前导
0
替换为.
, you can use , 您可以使用
gsub("\\G0", ".", dat, perl=TRUE)
Here, \G0
matches a 0
char at the start of string, and then every time after a successful match.在这里,
\G0
匹配字符串开头的0
字符,然后每次匹配成功后。 See this regex demo .请参阅此正则表达式演示。
If you need to replace each 0
in a string before the first letter you can use如果您需要在第一个字母之前替换字符串中的每个
0
,您可以使用
gsub("\\G[^\\p{L}0]*\\K0", ".", dat, perl=TRUE)
Here, \G
matches start of string or end of the preceding successful match, [^\p{L}0]*
matches zero or more chars other than a letter and 0
, then \K
omits the matched text, and then 0
matches the 0
char and it is replaced with a .
这里,
\G
匹配字符串的开头或前面成功匹配的结尾, [^\p{L}0]*
匹配零个或多个字符而不是字母和0
,然后\K
省略匹配的文本,然后0
匹配0
字符,它被替换为.
. . See this regex demo .
请参阅此正则表达式演示。
See the R demo online :在线查看 R 演示:
dat <- c("00000000AAAAAAAAAA0AAAAAAAAAA0AAAAAAAAAAAAAAAAAAAAAAAAD0","102030405000AZD")
gsub("\\G0", ".", dat, perl=TRUE)
## [1] "........AAAAAAAAAA0AAAAAAAAAA0AAAAAAAAAAAAAAAAAAAAAAAAD0"
## [2] "102030405000AZD"
gsub("\\G[^\\p{L}0]*\\K0", ".", dat, perl=TRUE)
## [1] "........AAAAAAAAAA0AAAAAAAAAA0AAAAAAAAAAAAAAAAAAAAAAAAD0"
## [2] "1.2.3.4.5...AZD"
This is really hard.这真的很难。 So I tried to do it with a custom function:
所以我尝试使用自定义 function 来做到这一点:
library(stringr)
dat<-("00000000AAAAAAAAAA0AAAAAAAAAA0AAAAAAAAAAAAAAAAAAAAAAAAD0")
Zero_Replacer <- function(x) {
x <- str_split(x, '[A-Za-z]', 2)
x[[1]][1] <- str_replace_all(x[[1]][1], "0", ".")
paste0(x[[1]][1], x[[1]][2])
}
Zero_Replacer(dat)
Output: Output:
[1] "........AAAAAAAAA0AAAAAAAAAA0AAAAAAAAAAAAAAAAAAAAAAAAD0"
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