2019-12-13 字符串的处理

提取字符串

> date()

[1] "Fri Dec 13 18:37:55 2019"

> substr(date(),2,4) #  from 2 to 4

[1] "ri "

strtrim(date(),8)    #前8位

[1] "Fri Dec "

字符串分割

>strsplit(date(),split = " ")

[[1]]

[1] "Fri"      "Dec"      "13"       "18:50:26""2019"    

> a=strsplit(date(),split = "

")

> a

[[1]]

[1] "Fri"      "Dec"      "13"       "18:51:05""2019"    

> a[[1]]

[1] "Fri"      "Dec"      "13"       "18:51:05""2019"   

> a[[1]][4]

[1] "18:51:05"

字符替换

sub("apple","banana","appleis wonderful")  #old,new,x

[1] "banana is wonderful"

> sub("apple","banana","apple

is apple")

[1] "banana is apple"

> gsub("apple","banana","apple

is apple")

[1] "banana is banana"

字符串的合并

> paste("a value:",88)#默认分割符为空格

[1] "a value: 88"

> paste("a value:",88,sep =

"")

[1] "a value:88"

> paste("a value:",88,sep =

"and")

[1] "a value:and88"

> paste("a value:",88,sep =

" and ")

[1] "a value: and 88

有时转换行列名时比如TCGT-AN-BCGH,会变成TCGA.AN.BCGH，这个时候用代码进行切换

str_replace_all(x,"\\.","_")

探查是否存在某个字符串，并赋给新的字符串

path_m<-NULL

for( t in 1:length(needclinicdata$ajcc_pathologic_m)){

  if(str_detect(needclinicdata$ajcc_pathologic_m[t],"M0")){

    path_m[t]<-0

  }else{

    if(str_detect(needclinicdata$ajcc_pathologic_m[t],"M1")){

      path_m[t]<-1

    }else{

      path_m[t]<-"NA"

    }

  }

}