DiNUCindex_RNA: Di riboNucleotide Index (DiNUCindex_RNA)
In ftrCOOL: Feature Extraction from Biological Sequences

Description Usage Arguments Details Value Note Examples

This function replaces di-ribonucleotides in a sequence with their physicochemical properties in the di-ribonucleotide index file.

DiNUCindex_RNA(
  seqs,
  selectedIdx = c("Rise (RNA)", "Roll (RNA)", "Shift (RNA)", "Slide (RNA)",
    "Tilt (RNA)", "Twist (RNA)"),
  threshold = 1,
  label = c(),
  outFormat = "mat",
  outputFileDist = ""
)

`seqs`	is a FASTA file containing ribonucleotide sequences. The sequences start with '>'. Also, seqs could be a string vector. Each element of the vector is a ribonucleotide sequence.
`selectedIdx`	DiNucIndex function works based on physicochemical properties. Users, select the properties by their ids or indexes in DI_RNA file. The default value of this parameter is a vector with ("Rise (RNA)", "Roll (RNA)", "Shift (RNA)", "Slide (RNA)", "Tilt (RNA)","Twist (RNA)") entries.
`threshold`	is a number between (0 , 1]. In selectedIdx, indices with a correlation higher than the threshold will be deleted. The default value is 1.
`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.

There are 22 physicochemical indexes in the di-ribonucleotide database.

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-1)*(number of selected di-ribonucleotide indexes) 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.

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.