r.branch(test, true_action[, test2, test2_action, ...], false_action) → any
test.branch(true_action[, test2, test2_action, ...], false_action) → any
Perform a branching conditional equivalent to if-then-else.
The branch command takes 2n+1 arguments: pairs of conditional expressions and commands to be executed if the conditionals return any value but false or nil (i.e., “truthy” values), with a final “else” command to be evaluated if all of the conditionals are false or nil.
You may call branch infix style on the first test. (See the second example for an illustration.)
r.branch(test1, val1, test2, val2, elseval)
is the equivalent of the Ruby statement
if test1
val1
elsif test2
val2
else
elseval
end
Example: Test the value of x.
x = 10
r.branch((x > 5), 'big', 'small').run(conn)
> "big"
Example: As above, infix-style.
x = 10
r.expr(x > 5).branch('big', 'small').run(conn)
> "big"
Example: Categorize heroes by victory counts.
r.table('marvel').map(
r.branch(
r.row['victories'] > 100,
r.row['name'].add(' is a superhero'),
r.row['victories'] > 10,
r.row['name'].add(' is a hero'),
r.row['name'].add(' is very nice')
)
).run(conn)
If the documents in the table marvel are:
[
{ :name => "Iron Man", :victories => 214 },
{ :name => "Jubilee", :victories => 49 },
{ :name => "Slava", :victories => 5 }
]
The results will be:
[
"Iron Man is a superhero",
"Jubilee is a hero",
"Slava is very nice"
]
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