إنشاء البيئات وفحصها

إنشاء بيئة جديدة

# Isolated environment (no parent chain)
e1 <- new.env(parent = emptyenv())
# Environment with global as parent
e2 <- new.env(parent = globalenv())
cat('e1 parent:', environmentName(parent.env(e1)), '\n')
cat('e2 parent:', environmentName(parent.env(e2)), '\n')

assign() — إضافة الروابط

e <- new.env(parent = emptyenv())
assign('x', 10, envir = e)
assign('y', 'hello', envir = e)
assign('z', TRUE, envir = e)
cat('x:', get('x', envir = e), '\n')
cat('y:', get('y', envir = e), '\n')

get() و mget()

e <- new.env(parent = emptyenv())
e$alpha <- 1
e$beta  <- 2
e$gamma <- 3
# Single
get('alpha', envir = e)
# Multiple
mget(c('alpha', 'beta', 'gamma'), envir = e)

ls() — سرد الروابط

e <- new.env(parent = emptyenv())
e$b_val  <- 2
e$a_val  <- 1
e$.secret <- 'hidden'
cat('Default ls:', ls(envir = e), '\n')
cat('All names :', ls(envir = e, all.names = TRUE), '\n')

استخدام exists() مع inherits

parent_e <- new.env(parent = emptyenv())
parent_e$shared <- 42
child_e  <- new.env(parent = parent_e)
# inherits=TRUE: finds shared in parent
cat('inherits TRUE:', exists('shared', envir = child_e, inherits = TRUE),  '\n')
# inherits=FALSE: only looks in child
cat('inherits FALSE:', exists('shared', envir = child_e, inherits = FALSE), '\n')

environmentName() و parent.env()

e <- new.env(parent = globalenv())
cat('Name of e     :', environmentName(e), '\n')
cat('Parent of e   :', environmentName(parent.env(e)), '\n')
cat('Name of global:', environmentName(globalenv()), '\n')

صياغة $ للبيئات

e <- new.env(parent = emptyenv())
e$pi_approx <- 3.14159
e[['e_approx']] <- 2.71828
cat('pi:', e$pi_approx, '\n')
cat('e :', e[['e_approx']], '\n')

استخدام rm() في بيئة محددة

e <- new.env(parent = emptyenv())
e$keep <- 1
e$remove_me <- 99
cat('Before:', ls(envir = e), '\n')
rm('remove_me', envir = e)
cat('After :', ls(envir = e), '\n')

as.list() لتفريغ بيئة

e <- new.env(parent = emptyenv())
e$x <- 10
e$y <- 20
e$z <- 30
bindings <- as.list(e)
cat('Class:', class(bindings), '\n')
cat('Length:', length(bindings), '\n')
str(bindings)

البيئات كجداول تجزئة

# Build a small key-value store
store <- new.env(hash = TRUE, parent = emptyenv())
keys   <- paste0('key_', 1:5)
values <- c(10, 20, 30, 40, 50)
for (i in seq_along(keys)) assign(keys[i], values[i], envir = store)
# Retrieve
cat('key_3 =', get('key_3', envir = store), '\n')
cat('All keys:', ls(store), '\n')

نسخ البيئات مقابل مشاركتها

e1 <- new.env(parent = emptyenv())
e1$val <- 100
e2 <- e1          # reference, not a copy
e2$val <- 999
cat('e1$val:', e1$val, '\n')  # 999, modified via e2!

# True copy:
e3 <- list2env(as.list(e1), parent = emptyenv())
e3$val <- 0
cat('e1$val after e3 change:', e1$val, '\n')  # still 999

تحقق سريع

إنشاء البيئات: أهم النقاط

config <- new.env(hash = TRUE, parent = emptyenv())
assign('host', 'localhost', envir = config)
assign('port', 5432L,       envir = config)
assign('db',   'mydb',      envir = config)
cat('Keys  :', ls(config), '\n')
cat('host  :', config$host, '\n')
cat('port  :', config$port, '\n')