EOF problem with ENTER

Discussion in 'Python' started by Prasoon, Jun 12, 2009.

  1. Prasoon

    Prasoon Guest

    I am new to python....
    I have written the following program in python.It is the solution of
    problem ETF in SPOJ.....


    #Euler Totient Function

    from math import sqrt
    def etf(n):
    i,res =2,n
    while(i*i<=n):
    if(n%i==0):
    res-=res/i
    while(n%i==0):
    n/=i
    i+=1
    if(n>1):
    res-=res/n
    return res

    def main():
    t=input()
    while(t):
    x=input()
    print str(etf(x))
    t-=1

    if __name__ == "__main__":
    main()


    The problem with my code is that whenever I press an extra "Enter"
    button instead of getting the cursor moved to the next line.....I get
    an error

    _SyntaxError- EOF while parsing and the program terminates.........._

    How should the code be modified so that even after pressing an extra
    "Enter" button the cursor get moved to the next line instead to
    throwing an exception......

    Prasoon
     
    Prasoon, Jun 12, 2009
    #1
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  2. Prasoon

    Chris Rebert Guest

    Use raw_input() instead of input() [at least until you switch to Python 3.x].
    input() does an implicit eval() of the keyboard input, which is (in
    part) causing your problem.
    Note that you'll need to explicitly convert the string raw_input()
    reads in using either int() or float() as appropriate.

    Still, you can't just enter extra lines and expect the program to
    automatically ignore them. You'll have to write the extra code
    yourself to handle empty input from the user.

    Cheers,
    Chris
     
    Chris Rebert, Jun 12, 2009
    #2
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  3. Prasoon

    Prasoon Guest

    I am using Python 2.6
    I have modified that code
    def main():
    t=int(raw_input())
    while(t):
    x=input()
    print str(etf(x))
    t-=1

    what should i do to handle new line and space......
    We used to get spaces and newline in C using their ASCII values ...can
    similar things be done here???

    Please write the code snippet(by modifying my code) from which i can
    understand something......!!!!!
     
    Prasoon, Jun 12, 2009
    #3
  4. Prasoon

    Prasoon Guest

    I am using Python 2.6
    I have modified that code
    def main():
    t=int(raw_input())
    while(t):
    x=int(raw_input())
    print str(etf(x))
    t-=1

    what should i do to handle new line and space......
    We used to get spaces and newline in C using their ASCII values ...can
    similar things be done here???

    Please write the code snippet(by modifying my code) from which i can
    understand something......!!!!!
     
    Prasoon, Jun 12, 2009
    #4
  5. You could do:

    while True:
    x = raw_input("Enter x=>")
    if x != "" : break # if you just press enter, raw_input returns an
    empty string

    Note that this still leaves out the case when you type something which
    is not a number.
    To cover this case, supposing that you need a float, you could do like
    this (NOT TESTED):

    while True:
    x_str = raw_input("Enter x=>")
    if x_str != "" : # to prevent having the error message on empty
    imput
    try:
    x = float(x_str)
    break # if it gets here the conversion in float was succesful
    except ValueError :
    print "The input '%s' cannot be converted in float" % x_str

    This code exits from the loop only when you supply a string that
    represents a floating number


    Ciao
     
    Francesco Bochicchio, Jun 12, 2009
    #5
  6. Prasoon

    Prasoon Guest


    I modified my code to

    #Euler Totient Function
    import sys
    from math import sqrt
    def etf(n):
    i,res =2,n
    while(i*i<=n):
    if(n%i==0):
    res-=res/i
    while(n%i==0):
    n/=i
    i+=1
    if(n>1):
    res-=res/n
    return res

    def main():
    while True:
    t=raw_input()
    if t!="":break
    t=int(t)
    while(t):
    while True:
    x=raw_input()
    if x!="":break
    x=int(x)
    print str(etf(x))
    t-=1

    if __name__ == "__main__":
    main()

    Now it is working fine ....thanks!!!
     
    Prasoon, Jun 12, 2009
    #6
  7. Hello Prasoon, there's still a major issue with your code, check out
    http://tottinge.blogsome.com/meaningfulnames/
    If your code is a private script targeted at your personal use, well I
    guess you can just ignore my comment. But I'm still impressed by how
    some of the python-list users have dived into your code with such ease.

    Regards,

    Jean-Michel
     
    Jean-Michel Pichavant, Jun 12, 2009
    #7
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