Scope modifiers: Difference between revisions
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>>> </lang> |
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More information on the scope modifiers can be found [http://docs.python.org/3.0/reference/simple_stmts.html#grammar-token-global_stmt here].<br> |
More information on the scope modifiers can be found [http://docs.python.org/3.0/reference/simple_stmts.html#grammar-token-global_stmt here].<br> |
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=={{header|R}}== |
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R uses lexical scoping – there is a nice introduction to this in the [http://cran.r-project.org/doc/FAQ/R-FAQ.html#Lexical-scoping FAQ on R]. There are no keywords related to scoping, but the [http://stat.ethz.ch/R-manual/R-patched/library/base/html/assign.html assign] function allows you to choose the environment in which a variable is assigned. The global assignment operators , '<<-' and '->>' are effectively shorthand for 'assign(..., envir=globalenv()). |
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<lang r> |
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x <- "defined in global env" |
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foo <- function() |
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{ |
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# Print existing value |
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print(x) # "defined in global env" |
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# define a local value and print it |
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x <- "defined inside foo" |
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print(x) # "defined inside foo" |
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# remove local value, reassign global value from within foo |
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rm(x) |
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assign("x", "reassigned global value", envir=globalenv()) |
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print(x) # "reassigned global value" |
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} |
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foo() |
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</lang> |
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=={{header|Tcl}}== |
=={{header|Tcl}}== |
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