Seaching a list for more than one string in python

Question

I wrote the below function to return True if it detects the string 'Device' in a list

def data_filter2(inner_list):
   return any(['Device' in str(x) for x in inner_list])

is there a way to search the list for more than one string and return True it it finds either one?

I tried

def data_filter2(inner_list):
   return any(['Device' or 'Drug' in str(x) for x in inner_list])

But this did not work.

Where's the dupe for... `any(el in text for el in ('string1', 'string2'))`... — Jon Clements, Jul 12 '16 at 16:02
@Ev.Kounis that's true, but with exactly two it's neater than nesting! — jonrsharpe, Jul 12 '16 at 16:04
@Ev.Kounisif you had more than 2 what is a more elegant way to do it? — Jstuff, Jul 12 '16 at 16:05
why not to play with return inner_list.index('Device') or inner_list.index('Drug')? — Sergius, Jul 12 '16 at 16:06
Possible duplicate of [Why does \`a == b or c or d\` always evaluate to True?](http://stackoverflow.com/questions/20002503/why-does-a-b-or-c-or-d-always-evaluate-to-true) — Łukasz Rogalski, Jul 12 '16 at 16:13

Moses Koledoye · Answer 1 · 2016-07-12T16:10:01.853

1

You could use a binary operator or or and depending on what you intend, but slightly different from how you've done it:

def data_filter2(inner_list):
   return any('Device' in str(x) or 'Drug' in str(x) for x in inner_list)

You could use a generator expression, and avoid creating a new list for your check.

edited Jul 12 '16 at 16:10

answered Jul 12 '16 at 16:02

Moses Koledoye

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@JonClements Thanks for the eye – Moses Koledoye Jul 12 '16 at 16:03

Ma0 · Answer 2 · 2016-07-12T18:55:08.453

1

What if you reverse the logic?

def data_filter2(inner_list):
   return any([str(x) in ['Device', 'Drug'] for x in inner_list])

This provides a framework that can "accept" more items to check for. Chaining or is not very pythonic to my eyes.

What is interesting to note here is the following:

alist_ = ['drugs', '123123']
astring = 'drug'


for i in range(len(alist_)):
    print(astring in alist_[i])
print('-----')

print(astring in alist_)

#prints:
#True
#False
#-----
#False

What this says is that searching for a string in a list requires the strings to be identical (case sensitive) but searching for a string in a string allows for substrings to return True as well.

edited Jul 12 '16 at 18:55

answered Jul 12 '16 at 16:06

Ma0

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This isn't strictly the same behaviour as the OP's original – jonrsharpe Jul 12 '16 at 16:07
i would say that this depends on the contents of `inner_list`. Strictly speaking it is indeed different. It will not work if each element of `inner_list` is a line read from a file for example. Boils down to __sub-sets__ and __super-sets__. – Ma0 Jul 12 '16 at 16:11
@Ev.Kounis is there a clever way of implementing regex so I dont have to type out Drug and Drugs? – Jstuff Jul 12 '16 at 18:06

score 1 · Answer 3 · answered Jul 12 '16 at 16:13

1

The solutions using any and comprenhensions are nice. Another alternative would be to use set intersection.

In [30]: bool(set(['aaa', 'foo']) & set(['foo']))
Out[30]: True

In [31]: bool(set(['aaa', 'foo']) & set(['bar']))
Out[31]: False

answered Jul 12 '16 at 16:13

Diego Allen

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well this is not equivalent to `in` though. But it might actually be closer to what OP wants. – Ma0 Jul 12 '16 at 16:14

score 0 · Answer 4 · answered Jul 12 '16 at 16:22

0

You can do it in one line like so:

def data_filter2(inner_list):
   return any([x in y for x in ['Device', 'Drug'] for y in inner_list])

answered Jul 12 '16 at 16:22

Ma0

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Seaching a list for more than one string in python

4 Answers4