| pushBack {base} | R Documentation |
Functions to push back text lines onto a connection, and to enquire how many lines are currently pushed back.
pushBack(data, connection, newLine = TRUE) pushBackLength(connection)
data |
a character vector. |
connection |
A connection. |
newLine |
logical. If true, a newline is appended to each string pushed back. |
Several character strings can be pushed back on one or more occasions.
The occasions form a stack, so the first line to be retrieved will be
the first string from the last call to pushBack. Lines which
are pushed back are read prior to the normal input from the
connection, by the normal text-reading functions such as
readLines and scan.
Pushback is only allowed for readable connections.
pushBack returns nothing.
pushBackLength returns number of lines currently pushed back.
zz <- textConnection(LETTERS)
readLines(zz, 2)
pushBack(c("aa", "bb"), zz)
pushBackLength(zz)
readLines(zz, 1)
pushBackLength(zz)
readLines(zz, 1)
readLines(zz, 1)
close(zz)