In python, it's possible to use the is
keyword to check for contains, e.g.
>>> 3 in [1,2,3,4,5]
True
But this doesn't yield the same output if it's checking whether a list of a single integer is inside the reference list [1,2,3,4,5]
:
>>> [3] in [1,2,3,4,5]
False
Also, checking a subsequence in the reference list cannot be achieved with:
>>> [3,4,5] in [1,2,3,4,5]
False
Is there a way to have a function that checks for subsequence such that the following returns true? e.g. a function call x_in_y()
:
>>> x_in_y([3,4,5], [1,2,3,4,5])
True
>>> x_in_y([3], [1,2,3,4,5])
True
>>> x_in_y(3, [1,2,3,4,5])
True
>>> x_in_y([2,3], [1,2,3,4,5])
True
>>> x_in_y([2,4], [1,2,3,4,5])
False
>>> x_in_y([1,5], [1,2,3,4,5])
False
Maybe something from itertools
or operator
?
(Note, the input lists can be non-unique)
x_in_y()
can be implemented by slicing the original list and comparing the slices to the input list:
def x_in_y(query, base):
try:
l = len(query)
except TypeError:
l = 1
query = type(base)((query,))
for i in range(len(base)):
if base[i:i+l] == query:
return True
return False
Change range
to xrange
if you are using Python2.
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