When it is required to check if two list of tuples are identical, the '==' operator is used. The '==' operator checks to see if two iterables are equal or not.
Tuple Matching in Python is a method of grouping the tuples by matching the second element in the tuples. It is achieved by using a dictionary by checking the second element in each tuple in python programming. However, we can make new tuples by taking portions of existing tuples. tup1 = ();
To compare tuples, just use the == operator, like this: let singer = ("Taylor", "Swift") let alien = ("Justin", "Bieber") if singer == alien { print("Matching tuples!") } else { print("Non-matching tuples!") }
Tuples are compared position by position: the first item of the first tuple is compared to the first item of the second tuple; if they are not equal (i.e. the first is greater or smaller than the second) then that's the result of the comparison, else the second item is considered, then the third and so on.
See Common Sequence Operations:
Sequences of the same type also support comparisons. In particular, tuples and lists are compared lexicographically by comparing corresponding elements. This means that to compare equal, every element must compare equal and the two sequences must be of the same type and have the same length.
Also Value Comparisons for further details:
Lexicographical comparison between built-in collections works as follows:
- For two collections to compare equal, they must be of the same type, have the same length, and each pair of corresponding elements must compare equal (for example,
[1,2] == (1,2)
is false because the type is not the same).- Collections that support order comparison are ordered the same as their first unequal elements (for example,
[1,2,x] <= [1,2,y]
has the same value asx <= y
). If a corresponding element does not exist, the shorter collection is ordered first (for example,[1,2] < [1,2,3]
is true).
If not equal, the sequences are ordered the same as their first differing elements. For example, cmp([1,2,x], [1,2,y]) returns the same as cmp(x,y). If the corresponding element does not exist, the shorter sequence is considered smaller (for example, [1,2] < [1,2,3] returns True).
Note 1: <
and >
do not mean "smaller than" and "greater than" but "is before" and "is after": so (0, 1) "is before" (1, 0).
Note 2: tuples must not be considered as vectors in a n-dimensional space, compared according to their length.
Note 3: referring to question https://stackoverflow.com/questions/36911617/python-2-tuple-comparison: do not think that a tuple is "greater" than another only if any element of the first is greater than the corresponding one in the second.
The Python documentation does explain it.
Tuples and lists are compared lexicographically using comparison of corresponding elements. This means that to compare equal, each element must compare equal and the two sequences must be of the same type and have the same length.
The python 2.5 documentation explains it well.
Tuples and lists are compared lexicographically using comparison of corresponding elements. This means that to compare equal, each element must compare equal and the two sequences must be of the same type and have the same length.
If not equal, the sequences are ordered the same as their first differing elements. For example, cmp([1,2,x], [1,2,y]) returns the same as cmp(x,y). If the corresponding element does not exist, the shorter sequence is ordered first (for example, [1,2] < [1,2,3]).
Unfortunately that page seems to have disappeared in the documentation for more recent versions.
a = ('A','B','C') # see it as the string "ABC"
b = ('A','B','D')
A is converted to its corresponding ASCII ord('A') #65
same for other elements
So,
>> a>b # True
you can think of it as comparing between string (It is exactly, actually)
the same thing goes for integers too.
x = (1,2,2) # see it the string "123"
y = (1,2,3)
x > y # False
because (1 is not greater than 1, move to the next, 2 is not greater than 2, move to the next 2 is less than three -lexicographically -)
The key point is mentioned in the answer above
think of it as an element is before another alphabetically not element is greater than an element and in this case consider all the tuple elements as one string.
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