Python syntax - cannot see why receiving syntax error

Question

I'm working though a course on Python. The following code is meant to count the vowels in a string. I typed it out as I thought it should be and did not work. I then cut n paste from lecture notes and it did work.

But I cannot see what the difference is! I've commented out my non working expressions. The working expression is below it.

Why does mine not work?

    ## count the number of vowels in string s
s = 'azcbobobegghakl'
vowelcount = 0
for char in s:
    ## if char == 'a' or char = 'e' or char == 'i' or char == 'o' \
       ## or char == 'u':

    if char == 'a' or char == 'e' or char == 'i' \
       or char == 'o' or char == 'u':

         vowelcount += 1
print "Number of vowels: " + str(vowelcount)

Here is the error message:

%run "/var/folders/cs/31zvz_q925v_z3tmvj09dpyc0000gn/T/tmpCEB9ME.py"
File "/var/folders/cs/31zvz_q925v_z3tmvj09dpyc0000gn/T/tmpCEB9ME.py", line 4
if char == 'a' or char = 'e' or char == 'i' or char == 'o' \
                       ^
SyntaxError: invalid syntax

You can see that you are using a single = that means you are doing assignment operation rather than comparision. — Ankur Ankan
– Ankur Ankan, Commented Nov 7, 2013 at 15:07
I got such a big response to this question. Clearly many folk follow the Python tag and it has a strong community behind it. Thanks for the help on my syntax error I'm really glad to be picking this up — Doug Fir
– Doug Fir, Commented Nov 7, 2013 at 15:19

score 3 · Accepted Answer · 2013-11-07 15:13:56Z

3

You need to use == for comparison tests:

if char == 'a' or char == 'e' or char == 'i' \
   or char == 'o' or char == 'u':

= is only used for variable assignment.

Or, even better here would be to use in:

if char.lower() in "aeiou":

This code tests whether a lowercase version of char can be found in the string "aeiou". I added .lower() so that your code can handle uppercase vowels.

edited Nov 7, 2013 at 15:13

answered Nov 7, 2013 at 15:07

user2555451

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Comments

user1804599 · Accepted Answer · 2013-11-07 15:07:44Z

2

You want == instead of =.

I suggest using the following equivalent instead, as it’s more pythonic and more readable:

if char in 'aeiou':
    ...

answered Nov 7, 2013 at 15:07

user1804599

Comments

user1907906 · Accepted Answer · 2013-11-07 15:06:42Z

1

The ^ is pointing you to the exact error.

or char = 'e'

must be

or char == 'e'

answered Nov 7, 2013 at 15:06

user1907906

1 Comment

Doug Fir Over a year ago

Doh! Thank you Lutz Horn. And thanks for the tip on ^. Accepting shortly

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