• View
• Edit
• History
• Print

Basic Datatypes: Tuples

#############################

Once a tuple is created, it cannot be changed (immutable).

tup = ()   # Empty tuple. Don't use the variable name 'tuple' because it'll shadow a built-in function!

t = ('vader', 'luke', 'leia')
print t[0]   # vader
print t[:-1]   # ('vader', 'luke') , note that the result is a new tuple

print t.index('leia')   # 2
print 'luke' in t   # True

# CONVERSIONS between tuples and lists
t = ('a', 'b')   # a tuple
li = list(t)     # tuple -> list
print li         # ['a', 'b']

tu = tuple(li)   # list -> tuple
print tu         # ('a', 'b')

• Tuples are faster than lists.
• If you don't want to change a "list", use a tuple. It makes your code safer.
• You can use multi-variable assignments by writing a function that returns a tuple of all the values.

A pitfall

singleton = ('jabba')
print type(singleton)     # <type 'str'> , not a tuple!
singleton = ('jabba', )   # notice the comma at the end
print singleton           # ('jabba',) , now it's a tuple

Some tuple functions

Some examples

(MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY) = range(7)
print MONDAY     # 0
print SATURDAY   # 5