Predefined Data Types in parseΒΆ

behave uses the parse module (inverse of Python string.format) under the hoods to parse parameters in step definitions. This leads to rather simple and readable parse expressions for step parameters.

# -- FILE: features/steps/
from behave import given

@given('I have {number:d} friends')  #< Convert 'number' into int type.
def step_given_i_have_number_friends(context, number):
    assert number > 0

Therefore, the following parse types are already supported in step definitions without registration of any user-defined type:

Type Characters Matched Output Type
w Letters and underscore str
W Non-letter and underscore str
s Whitespace str
S Non-whitespace str
d Digits (effectively integer numbers) int
D Non-digit str
n Numbers with thousands separators (, or .) int
% Percentage (converted to value/100.0) float
f Fixed-point numbers float
e Floating-point numbers with exponent e.g. 1.1e-10, NAN (all case insensitive) float
g General number format (either d, f or e) float
b Binary numbers int
o Octal numbers int
x Hexadecimal numbers (lower and upper case) int
ti ISO 8601 format date/time e.g. 1972-01-20T10:21:36Z datetime
te RFC2822 e-mail format date/time e.g. Mon, 20 Jan 1972 10:21:36 +1000 datetime
tg Global (day/month) format date/time e.g. 20/1/1972 10:21:36 AM +1:00 datetime
ta US (month/day) format date/time e.g. 1/20/1972 10:21:36 PM +10:30 datetime
tc ctime() format date/time e.g. Sun Sep 16 01:03:52 1973 datetime
th HTTP log format date/time e.g. 21/Nov/2011:00:07:11 +0000 datetime
tt Time e.g. 10:21:36 PM -5:30 time