Examples"

In MLMOI: Estimating Frequencies, Prevalence and Multiplicity of Infection

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

moimport(file,...)

Basic data import

The function is called with moimport(<file>,...), where the mandatory argument <file> is a string specifying the path of the file to be imported. Consider the following dataset:

library(MLMOI)
rJava::.jpackage("MLMOI")
fig <- system.file("extdata/fig", "basic.png", package = "MLMOI")
knitr::include_graphics(fig, auto_pdf = TRUE)

provided by the package in the Excel file 'testDatabasic.xlsx'. The first column contains the sample IDs followed by marker columns. Marker labels are in the first row. All marker columns are of type 'STR' (default for argument molecular). The code below imports and transforms this dataset to standard format:

infile <- system.file("extdata", "testDatabasic.xlsx", package = "MLMOI")
Outfile <- moimport(file = infile)

The first six rows of the imported data are printed using the command:

head(Outfile)

Exporting the dataset in standard format

If export is not an absolute path, the dataset will be stored in the current working directory:

Outfile <- moimport(infile, export = "testDatabasicOut.xlsx")

Importing datasets with metadata {#meta}

The number of metadata columns are specified via argument nummtd. If Users want to retain metadata, keepmtd = TRUE need to be set. The dataset 'testDatametadata.xlsx' contains three metadata variables, as shown below:

library(MLMOI)
rJava::.jpackage("MLMOI")
fig <- system.file("extdata/fig", "metadata.png", package = "MLMOI")
knitr::include_graphics(fig, auto_pdf = TRUE)

The appropriate code for importing this dataset is:

infile <- system.file("extdata", "testDatametadata.xlsx", package = "MLMOI")
Outfile <- moimport(infile, nummtd = 3, keepmtd = TRUE)

The first six rows of the imported data are printed using the command:

head(Outfile)

If users forget to set nummtd, the import function regards the metadata columns as marker columns. This usually causes various warnings.

Importing different types of molecular markers

The Excel file 'testDatamt.xlsx' provided by the package contains different types of molecular data. This dataset is shown below

library(MLMOI)
rJava::.jpackage("MLMOI")
fig <- system.file("extdata/fig", "multi-type.png", package = "MLMOI")
knitr::include_graphics(fig, auto_pdf = TRUE)

Marker columns start from third column. They are from left to right of data type 'STR', 'amino-acid', 'SNP', 'SNP', 'amino-acid' and 'codon'. The argument molecular needs to be set as a vector:

infile <- system.file("extdata", "testDatamt.xlsx", package = "MLMOI")
Outfile <- moimport(infile, nummtd = 1, molecular = c('str','amino','snp','snp','amino','codon'))

The first six rows of the imported data are printed using the command:

head(Outfile)

Since the coding class of markers in this dataset are the default ones, the argument coding is not specified.

Different molecular types with different coding classes

If a dataset contains a molecular marker whose coding is not assumed as default in moimport, the argument coding needs to be set. Consider the following dataset:

library(MLMOI)
rJava::.jpackage("MLMOI")
fig <- system.file("extdata/fig", "multi-type-coding.png", package = "MLMOI")
knitr::include_graphics(fig, auto_pdf = TRUE)

called 'testDatamtc.xlsx' provided by the package. The molecular markers in columns 3 ('SNP'), 5 ('STR') and 6 ('amino-acid') are not in default coding. Therefore, the argument coding needs to be set:

infile <- system.file("extdata", "testDatamtc.xlsx", package = "MLMOI")
Outfile <- moimport(infile, nummtd = 1,
         molecular = c('snp', 'str', 'str', 'amino', 'snp', 'codon'),
         coding = c('iupac', 'integer', 'nearest', 'full', '4let', 'triplet'))

Here a warning is issued because the entry 'z' is not in coding 'iupac'. The last six rows of the imported data are printed using the command:

tail(Outfile)

It can be seen that the entry 'z' is deleted.

Data from several worksheets

The file 'testDatacomplex.xlsx' provided by the package contains datasets in multiple worksheets as shown below:

library(MLMOI)
rJava::.jpackage("MLMOI")
fig <- system.file("extdata/fig", "complex.png", package = "MLMOI")

knitr::include_graphics(fig)

The numbering determines the order of worksheets in the Excel file. Clearly, this is the case of multiple worksheet dataset. Hence the option multsheets = TRUE needs to be set. Notice that worksheet (2) is entered in transposed format. Thus, the option transposed needs to be set as a logical vector, specifying which worksheets are in transposed format. The following code imports the dataset:

infile <- system.file("extdata", "testDatacomplex.xlsx", package = "MLMOI")
Outfile <- moimport(infile, multsheets = TRUE, keepmtd = TRUE, nummtd = c(0, 2, 2, 0), transposed = c(FALSE, TRUE, FALSE, FALSE),
         molecular = list(c('str', 'str', 'snp', 'snp'),
                          c('amino', 'codon', 'snp', 'amino', 'codon'),
                          c('codon', 'str'),
                          c('str', 'amino', 'snp', 'str')),
         coding = list(rep(c('integer', '4let'), each = 2), 
                       c('1let', 'triplet', 'iupac', '3let', 'triplet'),
                       c('triplet', 'integer'),
                       c('integer', '1let', 'iupac', 'integer')))

Several warnings are issued because data in the first and second worksheets have several entry errors. The first seven rows of the imported data are printed using the command:

head(Outfile, n = 7)

First warning of worksheet (2), addresses an entry with consecutive amino acids. Notice that, in spite of the warning the consecutive amino acids got converted to their equivalent three-letter designations after all.

moimerge(file1, file2,...)

Merging datasets {#merge}

Consider the datasets 'testDatamerge1.xlsx' and 'testDatamerge2.xlsx' from the package:

library(MLMOI)
rJava::.jpackage("MLMOI")
fig <- system.file("extdata/fig", "merge.png", package = "MLMOI")
knitr::include_graphics(fig)

These datasets are already in standard format. Running the following code imports and merges the datasets:

infile1 <- system.file("extdata", "testDatamerge1.xlsx", package = "MLMOI")
infile2 <- system.file("extdata", "testDatamerge2.xlsx", package = "MLMOI")
outfile <- moimerge(infile1, infile2, nummtd1 = 1, nummtd2 = 2, keepmtd = TRUE)

A warning is issued because the metadata information of sample 'samid10' differs in two datasets, implying a data entry error. The first six rows of the imported data are printed using the command:

head(outfile, n = 6)

Users can set export = <Outfile> to export the merged dataset.

moimle(file,...)

Estimating parameters

Consider again the dataset 'testDatametadata.xlsx' in section Importing datasets with metadata. The following code derives the maximum-likelihood estimates (MLE) of the MOI parameter and lineage frequencies for each marker separately

infile <- system.file("extdata", "testDatametadata.xlsx", package = "MLMOI")
mle <- moimle(file = infile, nummtd = 3)
mle$locus1

Constraining parameters

Consider again the dataset 'testDatasetmerge2' from section Merging datasets.This dataset contains pathological data on marker 'position2', resulting in meaningless estimate $\lambda = 0$. By setting boundaries via argument bounds, the MLE for lineage frequencies is derived from profiling at the bounds using $\lambda_{min}$ or $\lambda_{max}$

infile <- system.file("extdata", "testDatamerge2.xlsx", package = "MLMOI")
moimle(file = infile, nummtd = 2, bounds = c(1.5, 2))

MLMOI documentation built on Jan. 11, 2020, 9:22 a.m.