Python if else within list comprehension

Asked Dec 29 '19 at 13:37

Active Dec 29 '19 at 13:42

Viewed 28 times

I am looking to use the lambda construct to create entries in list (which is basically a list of lists) that are of fixed length - 200. If the length is greater than 200, then I want to cut it 200 mark else pad it at the beginning. However, the following does not seem to work. Can anyone help on what is the right way to get this done using 1-line lambda.

P.S.: I have it done in multiple lines, but am wondering if I can make the above work.

features= [ r[:200] for r in reviews_ints if len(r) >= 200 else np.pad(r, (200 - len(r),0), 'constant', constant_values=(0)) ]

The error I get is:

File "<ipython-input-12-85a13ada1f6d>", line 1
    features= [ r[:200] for r in reviews_ints if len(r) >= 200 else np.pad(r, (200 - len(r),0), 'constant', constant_values=(0)) ]
                                                                  ^
SyntaxError: invalid syntax

Thanks

edited Dec 29 '19 at 13:42

accdias

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asked Dec 29 '19 at 13:37

Moni

2

That's a list comprehension, not a lambda. – DeepSpace Dec 29 '19 at 13:39
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Try it this way: `features = [r[:200] if len(r) >= 200 else np.pad(r, (200 - len(r), 0), 'constant', constant_values=(0)) for r in reviews_ints]` – accdias Dec 29 '19 at 13:39
2

You have an `if` **and** an `else`, so they need to come **before** the `for` statement (https://stackoverflow.com/a/4260304/4324028) – Bruno Lubascher Dec 29 '19 at 13:41

Python if else within list comprehension

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