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Python tuple element operations

Are there any built-in functions that allow elementary processing of tuples in Python 3? If not, what is the "pythonic" way of performing these operations?

Example. I want to take the percentage difference between aand band compare them with a certain threshold th.

>>> a = (1, 2, 4)
>>> b = (1.1, 2.1, 4.1)
>>> # compute pd = 100*abs(a-b)/a = (10.0, 5.0, 2.5)
>>> th = 3
>>> # test threshold: pd < th => (False, False, True)
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6 answers

display function

>>> a = (1, 2, 4)
>>> b = (1.1, 2.1, 4.1)
>>> map(lambda a,b: 100*abs(a-b)/a < 3, a, b)
[False, False, True]

EDIT

of course, instead of a map, you can use lists, for example, BrenBarn did http://docs.python.org/tutorial/datastructures.html#nested-list-comprehensions

EDIT 2 zip removed, thanks DSM indicate no zip needed

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, :

[f(aItem, bItem) for aItem, bItem in zip(a, b)]

., f - , -. :

[100*abs(aItem - bItem)/aItem < 3 for aItem, bItem in zip(a, b)]

, , , Numpy, , ( , -, ..) -.

+9

NumPy?

import numpy as np
a = np.array([1,2,4])
b = np.array([1.1, 2.1, 4.1])

pd = 100*abs(a-b)/a # result: array([ 10. ,   5. ,   2.5])
th = 3
pd < th # result: array([False, False,  True], dtype=bool)
+4

, , Python (map? reduce?), ( , ) :

[100*abs(j-b[i])/j < 3 for i,j in enumerate(a)]
[False, False, True]

@delnan , / :

[True if 100*abs(j-b[i])/j < 3 else False for i,j in enumerate(a)]
+1

, Pythonic :

a = (1, 2, 4) b = (1.1, 2.1, 4.1)

:

TEST = [100*abs(a[i]-b[i])/a[i] > th for i in range(len(A))]
0
def pctError(observed, expected):
    return (observed-expected)/expected * 100.0

a = (1, 2, 4)
b = (1.1, 2.1, 4.1)
th = 3

pctErrors = map(lambda t:pctError(*t), zip(a,b))
# returns [-9.091, -4.76, -2.44]

map(lambda x: x < th, pctErrors)
[x < th for x in pctErrors]
# both return [True, True, True]

# or if you always need absolute % errors
map(lambda x: abs(x) < th, pctErrors)
[abs(x) < th for x in pctErrors]
# both return [False, False, True]
0

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