How to generate a list with the content at a particular position from a tuple removed?-CodePudding

>>> x=('a', 'b', 'c', 'd')
>>> [x[i] for i in range(len(x)) if i != 2]
['a', 'b', 'd']

I have the above tuple with 4 elements. I want to generate an array with the 3rd element in the tuple removed.

Is this the most succinct and efficient way to express this operation?

CodePudding user response：

You could use slice notation to do so.

>>> x = ("a", "b", "c", "d")
>>> result = list(x[:2]   x[3:])
>>> print(result)
['a', 'b', 'd']

At such a small scale, the difference in performance would be insignificant, but if we really want to measure it.

import timeit


stmt_range = """
x = ("a", "b", "c", "d")
result = [x[i] for i in range(len(x)) if i != 2]
"""


stmt_slice = """
x = ("a", "b", "c", "d")
result = list(x[:2]   x[3:])
"""

print(min(timeit.Timer(stmt=stmt_range).repeat(7, 100000)))
print(min(timeit.Timer(stmt=stmt_slice).repeat(7, 100000)))

Outputs

0.041514699998515425
0.0190705999993952

So the use of slice notation would be slightly faster.

CodePudding user response：

Convert the tuple to a list and then use the pop method. This avoids iteration and you can even make it a function.

def remove(tup, idx):
    l = list(tup)
    l.pop(idx)
    return l

This is my first time using the timeit module, but here is what I got.

import timeit

x = tuple([i for i in range(10000)])

def myfunc (tup, idx):
    l = list(tup)
    l.pop(idx)
    return l

def shadow(tup, idx):
    l = list(tup)
    del l[idx]
    return l

print("juanpa.arrivillaga")
print(timeit.timeit("[e for i,e in enumerate(x) if i != 2]", setup = "from __main__ import x", number=10000))

print("Antoine Delia")
print(timeit.timeit("list(x[:2]   x[3:])", setup = "from __main__ import x", number=10000))

print("My solution")
print(timeit.timeit(stmt="myfunc(x,2)", setup = "from __main__ import myfunc, x", number=10000))

print("ShadowRanger")
print(timeit.timeit(stmt="shadow(x,2)", setup = "from __main__ import shadow, x", number=10000))

Output:

juanpa.arrivillaga
9.834354800000256
Antoine Delia
2.695629099999678
My solution
0.6217948999997134
ShadowRanger
0.6193107999997665