Print vs return, Python Programming

Print vs Return

Here are two different method declarations:

def f1(x):

print x + 1 def f2(x):

return x + 1

What happens when  we call them?

>>> f1(3)


>>> f2(3)



It looks like they behave in exactly the similar way.  But they don't, exactly.  Look at this example:


>>> print(f1(3))



>>> print(f2(3))



In the case of f1, the function, when  calculated, prints 4; then  it gives the value  None, which  is given by the Python file. In the case of f2, it does not give  anything, but it gives 4, which  is printed by the Python core. Finally, we may look the difference here:


>>> f1(3) + 1


Traceback (most recent call last):

File "", line 1, in ?

TypeError: unsupported operator type(s) for +: 'NoneType' and 'int'

>>> f2(3) + 1



In the ?rst case, the function does not give a value,  so there  is nothing to include  to 1, and an error is created. In the second  type, the function gives the value  4, which  is included to 1, and  the result,  5, is output by the Python read-eval-print loop.

Print  is very needful  for debugging. It is very important to know  that you may print  out as many  values as you want  in one line:


>>> x = 100

>>> print 'x', x, 'x squared', x*x, 'xiv', 14

x 100 x squared 10000 xiv 14


We have also snuck in another data type on you: strings. A string  is a sequence of words. You can build a string  using  single or double quotes;  and access individual elements of strings using indexing.


>>> s1 = 'hello world'

>>> s2 = "hello world"

>>> s1 == s2


>>> s1[3]



As you  may  see,  indexing indicates  to the  extraction of a particular element of a string,  by using square brackets [i] where i is a number that  identi?es the  location  of the  character that  you wish to extract (note that the indexing starts  with 0 ).


Posted Date: 8/9/2012 7:01:08 AM | Location : United States

Related Discussions:- Print vs return, Assignment Help, Ask Question on Print vs return, Get Answer, Expert's Help, Print vs return Discussions

Write discussion on Print vs return
Your posts are moderated
Related Questions
Suppose the cover price of a book is $24.95, but bookstores get a 40% discount. Shipping costs $3 for the first copy and 75 cents for each additional copy. What is the tota

Programming models Just  as there  are several methods for organizing entire  software systems, there  are  different strategies for formally expressing computational processe

Procedures as first-class objects In Python, unlike  many  other  languages, methods are behave in much  the same way as num­ bers:  they  can be stored as values  of variable

protocol rdt2.2 considers there is a bit errors between sender to receiver and also from receiver to sender. So now we have to consider checking bit errors introduced in reply from

Print vs Return Here are two different method declarations: def f1(x): print x + 1 def f2(x): return x + 1 What happens when  we call them? >>> f1(3) 4 >>

There are three seating categories at a stadium. For a softball game, Class A seats cost $15, Class B seats cost $12, and Class C seats cost $9. Write a program that asks how many

Variables We cannot  go very far without variables. A variable is a value related to a name that we can bind  to have a particular value  and  then  later use in an expression.

Data array A has data series from 1,000,000 to 1 with step size 1, which is in perfect decreasing order. Data array B has data series from 1 to 1,000,000, which is in random order.

Write a program that requests a password after the author/program information is displayed. Make the password "hello". The program should then ask the user for their name: if the n

Interacting with the environment Computer systems have  to communicate with  the world around them,  getting information about  the external world, and  taking  actions  to cha