Hi All,
I found the function get() which returns an object.
My whole function looks like this:
-- cut --
#-------------------------------------------------------------------------------
# Module : t_load_dataset.R
# Author : Georg Maubach
# Date : 2016-08-15
# Update : 2016-08-15
# Description : Load dataset and print information on contents
# Source System : R 3.3.0 (64 Bit)
# Target System : R 3.3.0 (64 Bit)
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
#--------1---------2---------3---------4---------5---------6---------7---------8
t_module_name = "t_load_dataset"
t_version = "2016-08-15"
t_status = "released"
cat(
paste0("\n",
t_module_name, " (Version: ", t_version, ", Status: ", t_status,
")", "\n", "\n",
"Copyright (C) Georg Maubach 2016
This software comes with ABSOLUTELY NO WARRANTY.", "\n", "\n"))
# If do_test is not defined globally define it here locally by
un-commenting it
# Switch t_do_test to TRUE to run test
t_do_test <- FALSE
# [ Function Defintion
]--------------------------------------------------------
t_load_dataset <- function(file_path,
file_name) {
# Loads and RData file with all objects in it and prints information on
its
# contents
#
# Args:
# file_path (string):
# String with path name.
# file_name (string):
# String with file name.
#
# Operation:
# Loads the RData file with all its objects, stores the objects in the
# global environment .GlobalEnv and prints information about the
objects.
#
# Usage:
# The function is designed to work only on data frames.
#
# Returns:
# Nothing, but stores loaded objects directly into the global
environment.
#
# Error handling:
# None.
#-----------------------------------------------------------------------------
cat("----------------------- [ t_load_dataset() ]
----------------------\n\n")
file_location <- file.path(file_path, file_name)
cat(paste0('Loading ', file_location, " ...\n\n"))
dataset_list <- load(file = file_location,
envir = .GlobalEnv)
cat(paste0(
length(dataset_list),
" dataset(s) loaded:\n"))
cat(dataset_list)
cat("\n\n")
for (dataset in dataset_list) {
cat(paste0("Dataset '", dataset, "' contains ",
nrow(get(dataset, envir = .GlobalEnv)),
" cases in ",
ncol(get(dataset, envir = .GlobalEnv)),
" variables:\n"))
cat(names(get(dataset, envir = .GlobalEnv)))
cat("\n\n")
}
cat("------------------------------ [ Done ]
---------------------------\n\n")
}
# [ Test Defintion
]------------------------------------------------------------
t_test <- function(do_test = FALSE) {
if (do_test == TRUE) {
# Example dataset
var1 <- c(1, 2, 3)
var2 <- c(4, 5, 6)
d_data1 <- data.frame(var1, var2)
var3 <- c(7, 8, 9)
var4 <- c(10, 11, 12)
d_data2 <- data.frame(var3, var4)
# Save datasets
v_file_name <- "test_t_load_dataset.RData"
save(file = file.path(getwd(),
v_file_name),
list = c("d_data1", "d_data2"))
# Call function
t_load_dataset(file_path = getwd(), file_name = v_file_name)
# Cleanup
unlink(file.path(getwd(), v_file_name))
}
}
# [ Test Run
]------------------------------------------------------------------
t_test(do_test = t_do_test)
# [ Clean up
]------------------------------------------------------------------
rm("t_module_name", "t_version", "t_status", "t_do_test", "t_test")
# EOF
-- cut --
I will include it later the toolbox of R function on Sourceforge.net.
Kind regards
Georg
Von: g.maub...@weinwolf.de
An: r-help@r-project.org,
Datum: 15.08.2016 10:51
Betreff: [R] Accessing an object using a string
Gesendet von: "R-help" <r-help-boun...@r-project.org>
Hi All,
I would like to access an object using a sting.
# Create example dataset
var1 <- c(1, 2, 3)
var2 <- c(4, 5, 6)
data1 <- data.frame(var1, var2)
var3 <- c(7, 8, 9)
var4 <- c(10, 11, 12)
data2 <- data.frame(var3, var4)
save(file = "c:/temp/test.RData", list = c("data1", "data2"))
# Define function
t_load_dataset <- function(file_path,
file_name) {
file_location <- file.path(file_path, file_name)
print(paste0('Loading ', file_location, " ..."))
cat("\n")
object_list <- load(file = file_location,
envir = .GlobalEnv)
print(paste(length(object_list), "dataset(s) loaded from",
file_location))
cat("\n")
print("The following objects were loaded:")
print(object_list)
cat("\n")
for (i in object_list) {
print(paste0("Object '", i, "' in '", file_name, "' contains:"))
str(i)
names(i) # does not work
}
}
I have only the character vector object_list containing the names of the
objects as strings. I would like to access the objects in object_list to
be able to print the names of the variables within the object (usuallly a
data frame).
Is it possible to do this? How is it done?
Kind regards
Georg
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______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
