### Install argparse R package

Source: https://github.com/trevorld/r-argparse/blob/master/README.rst

Demonstrates how to install the latest version of the 'argparse' package from CRAN and the development version from GitHub.

```R
install.packages("argparse")
remotes::install_github("trevorld/r-argparse")
```

--------------------------------

### Mutually Exclusive Groups with argparse

Source: https://github.com/trevorld/r-argparse/blob/master/README.rst

Demonstrates how to create mutually exclusive argument groups, ensuring that only one argument from the group can be provided at a time. Includes examples of parsing valid and invalid combinations.

```R
parser = ArgumentParser(prog='PROG')
group = parser$add_mutually_exclusive_group()
group$add_argument('--foo', action='store_true')
group$add_argument('--bar', action='store_false')
parser$parse_args('--foo')
parser$parse_args('--bar')
# Example of an error case:
# parser$parse_args(c('--foo', '--bar'))
```

--------------------------------

### Parse Arguments with R argparse

Source: https://github.com/trevorld/r-argparse/blob/master/README.rst

Parses command-line arguments using an R argparse parser. This example demonstrates how to pass arguments and access the parsed values.

```R
parser$parse_args(c('--foo', 'b', '--baz', 'Z'))
```

--------------------------------

### Basic Argument Parsing with argparse

Source: https://github.com/trevorld/r-argparse/blob/master/README.rst

Shows how to create an ArgumentParser object, add positional and optional arguments, print usage, and parse arguments from a character vector.

```R
library("argparse")
parser <- ArgumentParser(description='Process some integers')
parser$add_argument('integers', metavar='N', type="integer", nargs='+',
                    help='an integer for the accumulator')
parser$add_argument('--sum', dest='accumulate', action='store_const',
                    const='sum', default='max',
                    help='sum the integers (default: find the max)')
parser$print_help()
args <- parser$parse_args(c("--sum", "1", "2", "3") )
accumulate_fn <- get(args$accumulate)
print(accumulate_fn(args$integers))
```

--------------------------------

### Sub-commands with argparse

Source: https://github.com/trevorld/r-argparse/blob/master/README.rst

Shows how to implement sub-commands using argparse, allowing for different sets of arguments to be handled based on a sub-command specified on the command line.

```R
# create the top-level parser
parser = ArgumentParser(prog='PROG')
parser$add_argument('--foo', action='store_true', help='foo help')
subparsers = parser$add_subparsers(help='sub-command help')

# create the parser for the "a" command
parser_a = subparsers$add_parser('a', help='a help')
parser_a$add_argument('bar', type='integer', help='bar help')

# create the parser for the "b" command
parser_b = subparsers$add_parser('b', help='b help')
parser_b$add_argument('--baz', choices='XYZ', help='baz help')

# parse some argument lists
parser$parse_args(c('a', '12'))
```

--------------------------------

### Argument Groups in argparse

Source: https://github.com/trevorld/r-argparse/blob/master/README.rst

Illustrates how to use argument groups to organize related command-line arguments, including adding descriptions to groups.

```R
parser = ArgumentParser(prog='PROG', add_help=FALSE)
group1 = parser$add_argument_group('group1', 'group1 description')
group1$add_argument('foo', help='foo help')
group2 = parser$add_argument_group('group2', 'group2 description')
group2$add_argument('--bar', help='bar help')
parser$print_help()
```

--------------------------------

### Print Help Message with R argparse

Source: https://github.com/trevorld/r-argparse/blob/master/README.rst

Prints the help message for an R argparse parser. This is useful for users to understand the available arguments and their usage.

```R
parser$print_help()
```

--------------------------------

### Print Help Message for Sub-command 'b' with Choices in R argparse

Source: https://github.com/trevorld/r-argparse/blob/master/README.rst

Prints the help message for a sub-command ('b') that includes an optional argument with predefined choices ('X', 'Y', 'Z') in R argparse.

```R
parser_b$print_help()
```

--------------------------------

### Print Help Message for Sub-command 'a' in R argparse

Source: https://github.com/trevorld/r-argparse/blob/master/README.rst

Prints the help message for a specific sub-command ('a') within an R argparse structure. This helps in understanding the arguments specific to that sub-command.

```R
parser_a$print_help()
```

--------------------------------

### Logical Type with Store Action in R-argparse

Source: https://github.com/trevorld/r-argparse/blob/master/NEWS.md

Adds a warning when 'logical' type is used with 'store' action in add_argument, recommending 'store_true' or 'store_false' for clarity.

```R
# Conceptual example triggering the warning
# parser$add_argument('--flag', type='logical', action='store', help='A logical flag')
```

--------------------------------

### Support for Formatter Class in R-argparse

Source: https://github.com/trevorld/r-argparse/blob/master/NEWS.md

Introduces support for the 'formatter_class' argument in ArgumentParser, allowing customization of help message formatting.

```R
# Conceptual example with formatter_class
# parser <- ArgumentParser(formatter_class='argparse::RawTextHelpFormatter')
# parser$add_argument('--help-text', help='Help text with raw formatting')
```

--------------------------------

### Add Version Action in R-argparse

Source: https://github.com/trevorld/r-argparse/blob/master/NEWS.md

Introduces the capability to display the program's version using the 'version' action in the add_argument function.

```R
parser$add_argument('--version', action='version', version='1.0.7')
```

--------------------------------

### Support for Choices Argument in R-argparse

Source: https://github.com/trevorld/r-argparse/blob/master/NEWS.md

Adds initial support for the 'choices' argument in parser$add_argument, allowing specification of allowed values for an argument.

```R
# Conceptual example with choices
# parser$add_argument('--mode', choices=c('fast', 'slow'), help='Execution mode')
```

--------------------------------

### Find Python 2.7 Binary in R-argparse

Source: https://github.com/trevorld/r-argparse/blob/master/NEWS.md

Updates find_python_cmd to also search for a 'python2.7' binary, improving compatibility with older Python versions.

```R
# Conceptual check for python2.7
# python2_cmd <- findpython::find_python_cmd(version='2.7')
# print(paste('Found Python 2.7:', python2_cmd))
```

--------------------------------

### Handle Unicode Arguments in R-argparse

Source: https://github.com/trevorld/r-argparse/blob/master/NEWS.md

Enhances the package's ability to handle Unicode characters in arguments and options, improving internationalization support.

```R
# Example demonstrating Unicode argument handling (conceptual)
# parser$add_argument('--unicode-option', type='character', help='An option with Unicode characters')
```

--------------------------------

### Find Python Command in R-argparse

Source: https://github.com/trevorld/r-argparse/blob/master/NEWS.md

Utilizes the findpython::find_python_cmd function for more robust detection of Python binaries.

```R
# Conceptual usage of find_python_cmd
# python_cmd <- findpython::find_python_cmd()
# print(paste('Found Python:', python_cmd))
```

--------------------------------

### Set NULL Default in R-argparse

Source: https://github.com/trevorld/r-argparse/blob/master/NEWS.md

Enables explicit setting of a NULL default value for arguments using add_argument.

```R
# Conceptual example setting NULL default
# parser$add_argument('--optional', default=NULL, help='An optional argument')
```

--------------------------------

### Pass Character Vector to Metavar in R-argparse

Source: https://github.com/trevorld/r-argparse/blob/master/NEWS.md

Allows passing a character vector to the 'metavar' argument in add_argument, providing more flexibility in argument display.

```R
# Conceptual example of using character vector for metavar
# parser$add_argument('--files', metavar=c('FILE1', 'FILE2'), help='Input files')
```

--------------------------------

### Interactive vs Non-interactive Parse Behavior in R-argparse

Source: https://github.com/trevorld/r-argparse/blob/master/NEWS.md

Modifies the behavior of parse_args in interactive R sessions to throw an error instead of quitting after displaying a help message.

```R
# Conceptual example of parse_args behavior
# if (interactive()) {
#   tryCatch({
#     parser$parse_args()
#   }, error = function(e) {
#     print('Error displayed instead of quitting')
#   })
# } else {
#   parser$parse_args()
# }
```

--------------------------------

### Set Integer Type in R-argparse

Source: https://github.com/trevorld/r-argparse/blob/master/NEWS.md

Fixes a bug related to setting the 'integer' type for arguments using the add_argument function.

```R
# Conceptual example of setting argument type to integer
# parser$add_argument('--count', type='integer', help='A count value')
```

--------------------------------

### Handle Default Vector in R-argparse

Source: https://github.com/trevorld/r-argparse/blob/master/NEWS.md

Fixes a bug in parser$add_argument when a default vector is specified instead of a scalar value.

```R
# Conceptual example with default vector
# parser$add_argument('--items', default=c('a', 'b'), help='A list of items')
```

--------------------------------

### Handle Python Errors in R-argparse

Source: https://github.com/trevorld/r-argparse/blob/master/NEWS.md

Ensures that error messages from Python scripts are passed on to the user when parsing arguments.

```R
# Conceptual example of Python script execution and error handling
# tryCatch({
#   args <- parser$parse_args()
# }, error = function(e) {
#   print(paste('Python script error:', e$message))
# })
```

--------------------------------

### Silence R Error Output

Source: https://github.com/trevorld/r-argparse/blob/master/NEWS.md

This code snippet demonstrates how to silence the default R error handler when running scripts non-interactively. It sets a custom error option to quit without outputting 'Execution halted', which is useful for cleaner script execution.

```R
if (!interactive())
    options(error=function(e) quit('no', status = 1, runLast = FALSE))
```

=== COMPLETE CONTENT === This response contains all available snippets from this library. No additional content exists. Do not make further requests.