This function extracts from a text file the value(s) of a given parameter.
.getParam(params.lines, flag, flag.split, is.num = TRUE)a string corresponding to the name of the file
from which to extract the parameter value
a string corresponding to the parameter name to be
extracted and that must be present into the param.lines file
a string to choose the concerned type of parameter
(either " " or "^--.*--$"), depending on the type of parameter
file (containing values or filenames)
default TRUE. 
 If TRUE, the extracted
parameter is considered to be numeric and will be processed as such
A vector containing one or more values of type string
(if is.num = FALSE) or numeric (if is.num = TRUE).
## Create a skeleton folder with the default name ('FATE_simulation')
if (dir.exists("FATE_simulation")) unlink("FATE_simulation", recursive = TRUE)
PRE_FATE.skeletonDirectory()
## Create a Global_parameters file
PRE_FATE.params_globalParameters(name.simulation = "FATE_simulation"
                                 , required.no_PFG = 6
                                 , required.no_strata = 5
                                 , required.simul_duration = 100
                                 , required.seeding_duration = c(10,50)
                                 , required.seeding_timestep = 1
                                 , required.seeding_input = 100)
                                 
## Extract number of PFG
.getParam(params.lines = "FATE_simulation/DATA/GLOBAL_PARAMETERS/Global_parameters_V1.txt"
          , flag = "NO_PFG"
          , flag.split = " "
          , is.num = TRUE)
## ----------------------------------------------------------------------------------------- ##
                                
## Load example data