Package 'infix'

Simple Error Handling

Description

Use this method to handle errors. The function evaluates an expression, and if it raises an error then evaluates a second expression.

Usage

tryExcept(expr, except = { }, error = function(e) { })

expr %except% except

Arguments

expr	Expression to be evaluated.
except	Expression to be evaluated if expr raises an error. By default it is an empty expression.
error	Handler function for an error condition occurred during the evaluation of expr. It's output is not used, as the output in case of an error is the evaluation of except. By default it is an empty function.

Details

tryExcept is a wrapper around tryCatch, but it allows you to evaluate an expression except when an error occurs to the first expression argument expr. Note that, if expr raises an error, the code evaluated before the error will be in use.

Examples

# No errors are raised
tryExcept(stop())

# If 'expr' has no errors
tryExcept({
  foo <- "foo"
}, except = {
  foo <- "foo bar"
})
print(foo) # "foo"

# If 'expr' has an error
tryExcept({
  foo <- "foo"
  stop()
}, except = {
  foo <- "foo bar"
})
print(foo) # "foo bar"

# Running it with the infix operator
{foo <- "foo"} %except% {foo <- "foo bar"}
print(foo) # "foo"

{ foo <- "foo"
  stop()
} %except% {
  foo <- "foo bar"
}
print(foo) # "foo bar"

---

Construct Path to File

Description

Analogous to file.path(x, y).

Usage

x %//% y

Arguments

x, y	Character vectors.

Examples

"home" %//% "dir" # returns "home/dir"

---

Function Logical Operators

Description

Creates a function which returns the corresponding logical operation between what f1 and f2 return.

Usage

f1 %&% f2

f1 %|% f2

f1 %xor% f2

Arguments

f1, f2

Arbitrary predicate functions.

Details

To obtain the logical negation of what a function f returns, use base function Negate.

Examples

is.null.na <- is.null %|% is.na
all(is.null.na(NA), is.null.na(NULL)) # returns TRUE

---

Basic Infix Binary Operators

Description

Contains a number of infix binary operators that may be useful in day to day practices.

Operators

except

Simple Error Handling.

operators

Common Infix Operators.

funlogic

Function Logical Operators.

pipes

Package's 'magrittr' pipe-operators.

Author(s)

Maintainer: Ernest Benedito [email protected]

See Also

Useful links:

• http://github.com/ebeneditos/infix

• Report bugs at http://github.com/ebeneditos/infix/issues

---

Default value for NULL

Description

This infix function makes it easy to replace NULL's with a default value. It's inspired by the way that Ruby's or operation (`||`) works.

Usage

a %||% b

Arguments

a, b	If a is NULL, will return b; otherwise returns a.

Examples

1 %||% 2 # returns 1
NULL %||% 2 # returns 2

---

Value (non) Matching

Description

The logical negation of %in%.

Usage

x %!in% table

Arguments

x	Vector or NULL: the values to be (not) matched.
table	Vector or NULL: the values to be (not) matched against.

Examples

4 %!in% 1:3 # returns TRUE

---

Common Infix Operators

Description

Common Infix Operators

Infix Operators

paste0

Concatenate Strings (see ?"%+%").

file.path

Construct Path to File (see ?"%//%").

nomatch

Value (non) Matching (see ?"%!in%").

nil

Default value for NULL (see ?"%||%").

---

Concatenate Strings

Description

Analogous to paste0(x, y).

Usage

x %+% y

Arguments

x, y	Objects to be converted to character vectors.

Examples

"01" %+% "jan" %+% "1970" # returns "01jan1970"

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