How to compare sizes of python lists

You can use the cmp() function in Python to compare the sizes of two lists.

cmp() function syntax:

cmp(list1, list2)

Parameters:

list1 -- Comparison list. list2 – the list to compare.

Return value:

If the compared elements are of the same type, compare their values ​​and return the result.

If two elements are not of the same type, check whether they are numbers.

If it is a number, perform the necessary number cast and then compare. If the element of one side is a number, then the element of the other side is "bigger" (the number is "smallest"). Otherwise, the comparison is done in alphabetical order of the type names.

If one list reaches the end first, the other, longer list is "bigger".

If we exhaust the elements of both lists and all elements are equal, then the result is a tie, that is, a 0 is returned.

The following examples show how to use the cmp() function:

list1, list2 = [123, 'xyz'], [456, 'abc']print cmp(list1, list2);
print cmp(list2, list1);
list3 = list2 + [786];
print cmp(list2, list3)

The output results of the above examples are as follows:

-1
1
-1

There is no cmp function in the Python 3.X version. If you need to implement the comparison function, you need to introduce the operator module, which is suitable for any object.

Instance:

>>> import operator
>>> operator.eq('hello', 'name');
False
>>> operator.eq('hello', 'hello');
True

You can also compare directly:

Start the comparison sequentially from the first element, If they are equal, continue and return the first result that does not want to wait for element comparison. If all elements are compared equal, the longer list is larger. If the length is the same, the two lists are equal

a = [1,2,3]
b = [1,3,5]
c = [1,2,3,-1]
print(a < b, a < c, b < c)
print(a > b, a > c, b > c)
True True False
False False True

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