Check for camel case in Python

Question

I would like to check if a string is a camel case or not (boolean). I am inclined to use a regex but any other elegant solution would work. I wrote a simple regex

(?:[A-Z])(?:[a-z])+(?:[A-Z])(?:[a-z])+

Would this be correct? Or am I missing something?

Edit

I would like to capture names in a collection of text documents of the format

McDowell
O'Connor
T.Kasting

Edit2

I have modified my regex based on the suggestion in the comments

(?:[A-Z])(?:\S?)+(?:[A-Z])(?:[a-z])+

Answer 1

You could check if a string has both upper and lowercase.

def is_camel_case(s):
    return s != s.lower() and s != s.upper() and "_" not in s


tests = [
    "camel",
    "camelCase",
    "CamelCase",
    "CAMELCASE",
    "camelcase",
    "Camelcase",
    "Case",
    "camel_case",
]

for test in tests:
    print(test, is_camel_case(test))

Output:

camel False
camelCase True
CamelCase True
CAMELCASE False
camelcase False
Camelcase True
Case True
camel_case False

Answer 2

You probably want something more like:

(?:[A-Z][a-z]*)+

Altho that would allow all caps. You could avoid that with:

(?:[A-Z][a-z]+)+

Anchor the expression with ^ and $ or \z if required.

Answer 3

Convert your string to camel case using a library like inflection. If it doesn't change, it must've already been camel case.

from inflection import camelize

def is_camel_case(s):
    # return True for both 'CamelCase' and 'camelCase'
    return camelize(s) == s or camelize(s, False) == s

Answer 4

I think you might get away with just checking that the string has a capital with a lower case letter before it if(line =~ m/[a-z][A-Z]/). Just checking lower and upper fails on the given examples. ~Ben

Answer 5

sub_string= 'hiSantyWhereAreYou'  `Change the string here and try`
index=[x for x,y in enumerate(list(sub_string)) if(y.isupper())] `Finding the index 
of caps`
camel_=[]
temp=0
for m in index:
    camel_.append(sub_string[temp:m])
    temp=m
if(len(index)>0):
    camel_.append(sub_string[index[-1]::])
    print('The individual camel case words are', camel_) `Output is in list`
else:
    camel_.append(sub_string)
    print('The given string is not camel Case')

Answer 6

if you do not want strings starting with upper-case e.g Case and Camelcase to pass True. edit @william's answer:

def is_camel_case(s):
  if s != s.lower() and s != s.upper() and "_" not in s and sum(i.isupper() for i in s[1:-1]) == 1:
      return True
  return False



tests = [
"camel",
"camelCase",
"CamelCase",
"CAMELCASE",
"camelcase",
"Camelcase",
"Case",
"camel_case",
]

for test in tests:
   print(test, is_camel_case(test))

the results:

camel False
camelCase True
CamelCase True
CAMELCASE False
camelcase False
Camelcase False
Case False
camel_case False