In Python, is there a way to validate a user input in a certain format?
Solution 1
The standard (and language-agnostic) way of doing that is by using regular expressions:
import re
re.match('^[0-9]{2}-[0-9]{3}$', some_text)
The above example returns True
(in fact, a "truthy" return value, but you can pretend it's True
) if the text contains 2 digits, a hyphen and 3 other digits. Here is the regex above broken down to its parts:
^ # marks the start of the string
[0-9] # any character between 0 and 9, basically one of 0123456789
{2} # two times
- # a hyphen
[0-9] # another character between 0 and 9
{3} # three times
$ # end of string
I suggest you read more about regular expressions (or re, or regex, or regexp, however you want to name it), they're some kind of swiss army knife for a programmer.
Solution 2
In your case, you can use a regular expression:
import re
while True:
inp = input() # raw_input in Python 2.x
if re.match(r'[a-zA-Z0-9]{2}-[a-zA-Z0-9]{3}$', inp):
return inp
print('Invalid office code, please enter again:')
Note that in many other cases, you can simply try converting the input into your internal representation. For example, when the input is a number, the code should look like:
def readNumber():
while True:
try:
return int(input()) # raw_input in Python 2.x
except ValueError:
pass
user1186420
Updated on June 16, 2022Comments
-
user1186420 almost 2 years
In python, I'm asking the user to input an office code location which needs to be in the format: XX-XXX (where the X's would be letters)
How can I ensure that their input follows the format, and if it doesn't ask them to input the office code again?
Thanks!