Select columns of a matrix (or list of matrices) by name
Source:R/Utilities.R
select_cols_byname.Rd
Arguments indicate which columns are to be retained and which are to be removed. For maximum flexibility, arguments are extended regex patterns that are matched against column names.
Usage
select_cols_byname(
a,
retain_pattern = "$^",
remove_pattern = "$^",
ignore.case = FALSE,
perl = FALSE,
fixed = FALSE,
useBytes = FALSE
)
Arguments
- a
a matrix or a list of matrices
- retain_pattern
an extended regex or list of extended regular expressions that specifies which columns of
m
to retain. Default pattern ("$^") retains nothing.- remove_pattern
an extended regex or list of extended regular expressions that specifies which columns of
m
to remove. Default pattern ("$^") removes nothing.- ignore.case, perl, fixed, useBytes
Arguments passed to
grep()
.
Details
If a
is NULL
, NULL
is returned.
Patterns are compared against column names using extended regex.
If no column names of a
match the retain_pattern
, NULL
is returned.
If no column names of a
match the remove_pattern
, a
is returned.
Retaining columns takes precedence over removing columns, always.
Some typical patterns are:
"^Electricity$|^Oil$": column names that are EXACTLY "Electricity" or "Oil".
"^Electricity|^Oil": column names that START WITH "Electricity" or "Oil".
"Electricity|Oil": column names that CONTAIN "Electricity" or "Oil" anywhere within them.
Given a list of column names, a pattern can be constructed easily using the make_pattern
function.
RCLabels::make_or_pattern()
escapes regex strings using Hmisc::escaprRegex()
.
This function assumes that retain_pattern
and remove_pattern
have already been
suitably escaped.
Note that the default retain_pattern
and remove_pattern
("$^")
retain nothing and remove nothing.
If the row or column labels contain "[" or "]",
care should be taken to escape those characters.
Hmisc::escapeRegex()
is helpful in such situations.
Note that if all columns are removed from a
, NULL
is returned.
Examples
m <- matrix(1:16, ncol = 4, dimnames=list(c(paste0("i", 1:4)), paste0("p", 1:4))) %>%
setrowtype("Industries") %>% setcoltype("Commodities")
select_cols_byname(m,
retain_pattern = RCLabels::make_or_pattern(c("p1", "p4"),
pattern_type = "exact"))
#> p1 p4
#> i1 1 13
#> i2 2 14
#> i3 3 15
#> i4 4 16
#> attr(,"rowtype")
#> [1] "Industries"
#> attr(,"coltype")
#> [1] "Commodities"
select_cols_byname(m,
remove_pattern = RCLabels::make_or_pattern(c("p1", "p3"),
pattern_type = "exact"))
#> p2 p4
#> i1 5 13
#> i2 6 14
#> i3 7 15
#> i4 8 16
#> attr(,"rowtype")
#> [1] "Industries"
#> attr(,"coltype")
#> [1] "Commodities"
# Also works for lists and data frames
select_cols_byname(list(m,m), retain_pattern = "^p1$|^p4$")
#> [[1]]
#> p1 p4
#> i1 1 13
#> i2 2 14
#> i3 3 15
#> i4 4 16
#> attr(,"rowtype")
#> [1] "Industries"
#> attr(,"coltype")
#> [1] "Commodities"
#>
#> [[2]]
#> p1 p4
#> i1 1 13
#> i2 2 14
#> i3 3 15
#> i4 4 16
#> attr(,"rowtype")
#> [1] "Industries"
#> attr(,"coltype")
#> [1] "Commodities"
#>