Definition of .format? (Newbie question)

[Jan_97]

I'm completly new to python and I've only been learning it for about a week. I have over the last couple of days spent many hours watching tutorials and creating my own codes but there's this one thing I'm a little stuck upon. I will explain when we get there.


I'm having problems understanding how the .format works and what its uses are.

by definition I found this explanation.

Syntax : { } .format(value)

Parameters :
(value) : Can be an integer, floating point numeric constant, string, characters or even variables.

Returntype : Returns a formatted string with the value passed as parameter in the placeholder position.

This all seems well and good. However, in my partially self coded class example I can't figure out what the .format is used for.

Here is my code.

class meaning:
    def __init__(self,name,lastname,nickname):
     self.name = name
     self.lastname = lastname
     self.nickname = nickname
    def myfunc(self):
        return "{} {} {}".format(self.name, self.lastname,self.nickname)

dude1 = meaning ("John", "Cena" ,"The hulk")
dude2 = meaning ("Gordon", "Freeman", "MRMIME")

print (dude1.myfunc())
print (dude2.myfunc())

My question here is.

Why is .format necessary here? I found a tutorial suggesting I need to have it included and that I can't just use str instead. However, there are no digits in this function. Why do I need .format if it's just text?

Maybe I'm just very stupid, but I can't make sense of my own stuff. I just know I had to include it....

In this class however, I don't have .format included and it runs almost just the same.

class Person:
  def __init__(self, name, age):
    self.name = name
    self.age = age
  def myfunc(self):
      print ("Hello, my name is " + self.name)

p1 = Person ("Pyke", 36)
p1.myfunc()

print(p1.name)
print(p1.age)

What have I missed?

[metulburr]

Because this

      print ("Hello, my name is " + self.name)

is not pythonic. Not to mention messy. Especially if you have more than one you are "formatting" into the final string and at different indices. No one in python does it like this (at least not to format it).

This is much easier to read

"{} {} {}".format(self.name, self.lastname,self.nickname)

You can tell there are 3 inserts separated with a single space character. Its simple and easy to understand the string structure.

format also has a built-in mini language to allow extra things you can do to the final format without changing the variable itself

>>> num = 3.141592653589793
>>> '{:.2f}'.format(num)
'3.14'
>>> '{:.3f}'.format(num)
'3.142'
>>> '{:010.3f}'.format(num)
'000003.142'
>>> '{:10.2f}'.format(num)
'      3.14'
>>> '{:30}'.format(num)
'             3.141592653589793'
>>> '{:<30}'.format(num)
'3.141592653589793             '
>>> '{:,}'.format(123456789)
'123,456,789'
>>> '{0:b}'.format(255)
'11111111'
>>> num
3.141592653589793

more here
https://docs.python.org/3/library/string...i-language

[snippsat]

Also as new user you should use f-string,it's the future.
f-string are far more readable and concise,less prone to error than other ways of formatting.
Not that new,2.5-year ago in Python 3.6 f-string was new.

num = 3.141592653589793
>>> print(f'Area of a circle is equal to {num:.2f} times the radius squared,eg circle radius 5 has area: {5**2 * num:.1f}')
Area of a circle is equal to 3.14 times the radius squared,eg circle radius 5 has area: 78.5

>>> name = 'f-string'
>>> print(f"String formatting is called {name.upper():*^20}")
String formatting is called ******F-STRING******

# f-strings can take any Python expressions inside the curly braces.
>>> cost = 99.75999
>>> finance = 50000
>>> print(f'Toltal cost {cost + finance:.2f}')
Toltal cost 50099.76
  
>>> for word in 'f-strings are cool'.split():
...     print(f'{word.upper():~^20}')
...
~~~~~F-STRINGS~~~~~~
~~~~~~~~ARE~~~~~~~~~
~~~~~~~~COOL~~~~~~~~

[Skaperen]

Python is a very flexible language system. a great many things you might need to do have more than one way to do it. but, a particular way is often considered to be the best way to do each thing. this is referred to as "pythonic". usually, it is the way that best takes advantage of Python's great power. the community will often point you in that direction.

if you are new to programming and Python is your first programming language, it will be easy. if, like me, you programmed in other languages before (Python is probably my 20th language), then it can be harder since you will need to unlearn many of the things learned with other languages. try, as much as you can, to learn and follow the methods of pythonic programming. do not fear if it looks unfamiliar; just ask for any help you need. and welcome to the community. your new and great journey begins today.

[Jan_97]

Thanks for all the replies! I will take all of your tips in consideration!