read.and.check
Read data interactively and check that it satisfies conditions
Input is read interactively and checked against conditions specified
by the arguments what, lower, upper and
answer.in. If the input does not satisfy all the conditions,
an appropriate error message is produced and the user is prompted
to provide input. This process is repeated until a valid input value
is entered.
- Keywords
- utilities
Usage
read.and.check(message = "", what = numeric(), lower, upper, answer.in,
default)Arguments
- message
message displayed before prompting for user input.
- what
the type of
whatgives the type of data to be read.- lower
lower limit of input, for numeric input only.
- upper
upper limit of input, for numeric input only.
- answer.in
the input must correspond to one of the elements of the vector
answer.in, if supplied.- default
value assumed if user enters a blank line.
Value
The value of the valid input. When the default argument is
specified, a blank line is accepted as valid input and in this case
read.and.check returns the value of default.
Note
Since the function does not return a value until it receives valid input, it extensively checks the conditions for consistency before prompting the user for input. Inconsistent conditions will cause an error.