CODEWITHSUNDEEP
pythonregexpython-3.x
kflaw
kflaw

Reputation: 424

using regexp, how to find strings containing only uppercase or lowercase

I need to check the entire string for case. and only print those with all uppercase OR lowercase.

Here's the code I've written.

import re

lower = 'abcd'
upper = 'ABCD'
mix = 'aB'
mix2 = 'abcD'
exp = re.compile("[a-z]{2,}|[A-Z]{2,}")

lower_m = re.findall(exp,lower)
upper_m = re.findall(exp,upper)
mix_m = re.findall(exp,mix)
mix2_m = re.findall(exp,mix2)

print(lower_m)
print(upper_m)
print(mix_m)
print(mix2_m)

Upvotes: 1

Views: 6593

Answers (3)

dawg
dawg

Reputation: 103754

This works:

import re

st='''abcd
ABCD
aB
abcD'''

for line in st.splitlines():
    line=line.strip()
    if re.search(r'^[a-z]+$',line):
        print(line,'only lower')
        continue
    if re.search(r'^[A-Z]+$',line):
        print(line,'only upper')
        continue   
    if re.search(r'^[a-zA-Z]+$',line):
        print(line,'mixed case')

Upvotes: 0

Matt Bryant
Matt Bryant

Reputation: 4961

Use the upper() and lower() string methods, rather than a regex.

if string.lower() == string or string.upper() == string:
    print string

If only letters are allowed, also check that string.isalpha().

If a regex is necessary, the problem with yours is that you don't check the entire string.

exp = re.compile("^([a-z]{2,}|[A-Z]{2,})$")

This will ensure that the entire string needs to fit the pattern, rather than just part of it.

Upvotes: 6

Jon Clements
Jon Clements

Reputation: 142136

I don't see why you need to use a regex, but anyway:

if re.match('[a-z]+$', text) or re.match('[A-Z]+$', text):
    # is all lower or all upper

Which simplifies to:

if re.match('([a-z]+|[A-Z]+)$', text):
    # is all lower or all upper

Upvotes: 1

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