File I/O

var3.rb

Conditional I

# Assign three values.
a, b, c = 8, 10, 15
print "A: a = ", a, ", b = ", b, ", c = ", c, "\n"

# Compute three values, then assign three values.
a, b, c = 40, a + 11, a + b + c
print "B: a = ", a, ", b = ", b, ", c = ", c, "\n"

# Swap.
a, b = b, a
print "C: a = ", a, ", b = ", b, ", c = ", c, "\n"

# Extras on left get nil.
a, b, c = 2, 3
print "D: a = ", a, ", b = ", b, ", c = ", c, "\n"

# Extras on right get left behind
a, b, c = 11, 12, 13, 14, 15
print "E: a = ", a, ", b = ", b, ", c = ", c, "\n"

# The right can be an array, in which case the members are assigned to
# individual variables.
fred = [ 4, 5, 6, 7]
a, b, c = fred
print "F: a = ", a, ", b = ", b, ", c = ", c, "\n"

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A parallel assignment sets several variables at once. All right sides are computed before any variable is assigned, so all right side values are computed with the old variable values. This is very convenient for swapping two values without using a temporary.

When the right side is an array, the members of the array are broken out and assigned to individual variables.

File I/O

Conditional I