Python : SyntaxError: keyword can't be an expression

Question

Not sure where the issue is, i tried using multiple variables names to this dict with the same error:

>>> hostname=dict('172.16.1.75'='N-Switch', '172.16.1.76' = 'W-Switch', '172.16.1.77' = 'E-Switch')
SyntaxError: keyword can't be an expression

I am trying to create a dictionary for a script to change hostnames on assets based by calling their IP address as the key. any idea where the issue is?

To use the `dict` function, the keys must be passed as you would function parameters, meaning they must be valid indetifiers — Moses Koledoye, May 16 '17 at 09:17
You can only use valid Python identifiers as keyword arguments (including to the `dict()` callable). Use a `{...}` dict display instead. — Martijn Pieters, May 16 '17 at 09:18
Also see: http://stackoverflow.com/questions/10390606/python-syntaxerror-with-dict1-but-1-works — Chris_Rands, May 16 '17 at 09:18
Can someone provide an example, if I want to achieve this with `dict` ? — akash karothiya, May 16 '17 at 09:19

e4c5 · Answer 1 · 2017-05-17T04:32:59.683

3

The usual format for initiallizing a dict is like this

hostname=dict([('172.16.1.75','N-Switch'), ('172.16.1.76','W-Switch'), ('172.16.1.77', 'E-Switch')])

or more simply as given by Carles Mitjans in his answer (which appears to have been delete so adding the gist of it here for the benefit of < 10k users)

 hostname={'172.16.1.75':'N-Switch', '172.16.1.76' : 'W-Switch', '172.16.1.77' : 'E-Switch'}

This is in fact the more usual way of using dictionaries in python. The dict built in is used only when you are working with dynamic lists.

Also possible is a dictionary comprehension.

edited May 17 '17 at 04:32

answered May 16 '17 at 09:18

e4c5

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I think you're missing a parent container for the tuples – Moses Koledoye May 16 '17 at 09:19
yes, thanks for pointing out. – e4c5 May 16 '17 at 09:19

score 2 · Answer 2 · answered May 16 '17 at 09:17

2

I am not sure you are using valid syntax, try:

hostname={'172.16.1.75':'N-Switch', '172.16.1.76' : 'W-Switch', '172.16.1.77' : 'E-Switch'}

answered May 16 '17 at 09:17

apomene

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score 0 · Answer 3 · answered May 16 '17 at 09:17

As the error says, parameters can't be strings. The solution would be to create a dictionary using {} constructor:

hostname={'172.16.1.75':'N-Switch', '172.16.1.76' : 'W-Switch', '172.16.1.77' : 'E-Switch'}

If you wish to use the dict constructor you need to provide valid parameters as keys (not strings).

Python : SyntaxError: keyword can't be an expression

3 Answers3