CODEWITHSUNDEEP
pythonstringcomparison
Lebrunski
Lebrunski

Reputation: 3

Python: How would I compare two strings using a function with only one of the strings as an argument?

I've created a class, and I am unsure how to approach the following problem. Is it possible to create a function that will be able to do what is in the example? (For practical uses, I would be comparing dates and returning true if the day and month are the same but not necessarily the years are the same)

Example:

>>>strvar1 = 'abc-123'
>>>strvar2 = 'abc-456'
>>>strvar1.myfunction(strvar2)
True

Class code

class Date(object):
     def __init__(self, x0 = 1900, y0 = 1, z0 = 1):
        self.x = x0
        self.y = y0
        self.z = z0
     def __str__(self):
        date = str(self.x) + "-" + str(self.y).rjust(2, '0') + "-" + str(self.z).rjust(2, '0')
        return date  
     def myFunction(j):

So with the example it would look like:

d1 = Date(1999, 1, 1) //d1 = "1999-01-01"
d2 = Date(2000, 2, 2) //d2 = "2000-02-02"
d3 = Date(2001, 2, 2) //d3 = "2001-02-02"

>>>d1.myFunction(d2)
False
>>>d2.myFuction(d3)
True

Upvotes: 0

Views: 80

Answers (3)

kojiro
kojiro

Reputation: 77099

There's nothing wrong with a class-based approach, but functional programming has a solution for this too, in partial functions:

def make_has_same_month_day(d1):
    """return a function that takes a date
    and returns true if the month and day are the same as the enclosed date"""
    def has_same_month_day(d2):
        return d1.y == d2.y and d1.z == d2.z
    return has_same_month_day

This can also be written using functools.partial.

from functools import partial
def same_month_day(d1, d2):
    """return true if both dates have the same month and day"""
    return d1.y == d2.y and d1.z == d2.z
has_same_month_day = partial(same_month_day, d1)

Upvotes: 0

user3407196
user3407196

Reputation:

Yes absolutely, this is a reason for having classes. Read up on https://docs.python.org/2/tutorial/classes.html.

 def myFunction(self, cdate):
     return self.y == cdate.y and self.z == cdate.z

Upvotes: 1

Andrew
Andrew

Reputation: 381

If you are trying to perform a comparison before method invocation you could use the ternary operator to evaluate a condition then return the variable you want. An example is listed below written in JavaScript

var a = 1
var b = 2
myObj.myMethod( (a>b) ? a : b );

In the above example the ternary syntax 

(a>b) ? a : b

will evaluate a is greater than b then return a if true otherwise if a is less than b it will return b.

Ternary Wiki Link

Without knowing language you may want to check out the wiki page for your languages particular syntactical implementation.

Upvotes: 0

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