LocalPoSpKAAF {ftrCOOL}

Local Position Specific k Amino Acids Frequency (LocalPoSpKAAF)

Description

For each sequence, this function creates a feature vector denoted as (f1,f2, f3, …, fN), where fi = freq(i'th k-mer of the sequence) / i. It should be applied to sequences with the same length.

Usage

LocalPoSpKAAF(seqs, k = 2, label = c(), outFormat = "mat", outputFileDist = "")

Arguments

seqs

is a FASTA file with amino acid sequences. Each sequence starts with a '>' character. Also, seqs could be a string vector. Each element of the vector is a peptide/protein sequence.

k

is a numeric value which holds the value of k in the k-mers.

label

is an optional parameter. It is a vector whose length is equivalent to the number of sequences. It shows the class of each entry (i.e., sequence).

outFormat

(output format) can take two values: 'mat'(matrix) and 'txt'. The default value is 'mat'.

outputFileDist

shows the path and name of the 'txt' output file.

Value

The output depends on the outFormat parameter which can be either 'mat' or 'txt'. If outFormat is 'mat', the function returns a feature matrix for sequences with the same length such that the number of columns is (sequence length-k+1) and the number of rows is equal to the number of sequences. If the outFormat is 'txt', the output is written to a tab-delimited file.

Note

This function is provided for sequences with the same lengths. Users can use 'txt' option in outFormat for sequences with different lengths. Warning: If outFormat is set to 'mat' for sequences with different lengths, it returns an error. Also, when output format is 'txt', label information is not shown in the text file. It is noteworthy that 'txt' format is not usable for machine learning purposes if sequences have different sizes. Otherwise 'txt' format is also usable for machine learning purposes.

Examples

dir = tempdir()
ptmSeqsADR<-system.file("extdata/",package="ftrCOOL")
ptmSeqsVect<-as.vector(read.csv(paste0(ptmSeqsADR,"/ptmVect101AA.csv"))[,2])
mat<-LocalPoSpKAAF(seqs = ptmSeqsVect, k=2,outFormat="mat")

ad<-paste0(dir,"/LocalPoSpKaaF.txt")
filePrs<-system.file("extdata/proteins.fasta",package="ftrCOOL")
LocalPoSpKAAF(seqs = filePrs, k=1,outFormat="txt"
,outputFileDist=ad)

unlink("dir", recursive = TRUE)