Re: Testing for Null?

Collapse
This topic is closed.
X
X
 
  • Time
  • Show
Clear All
new posts
  • Terry Reedy

    Re: Testing for Null?



    Alex Bryan wrote:
    I am having a problem with a list value that is empty. I have a list of
    definitions called mainList. the 5th value in the list doesn't have
    anything in it. In this case, the values are definitions; also, in this
    case just the word cheese is defined. Here is my output to the console:
    >
    >
    5. a sprawling,weedy plant having small lavender or white flowers and
    round, flat, segmented fruits thought to resemble little wheels of cheese.
    6.
    7. an ingot or billet made into a convex, circular form by blows at the
    ends.
    >
    >
    I've made it so where the numbers, the period, and two spaces follow
    that, then the definition. However, as you can see in 6, there is
    nothing. Here is the code to print all this:
    >
    n=0
    >
    for x in mainList:
    if mainList[n] == "":
    print "Error on this definition"
    else:
    print str(n+1)+". "+str(mainL ist[n])
    n=n+1
    >
    Now the two "" is where I need to figure out if it is empty. What is up
    right now doesn't work; or at least doesn't give the desired result. So
    I need to know how to write the if statement to make it work. This
    should be simple, but I just don't know how to do it, never had this
    problem before.
    My guess is that your 'empty' value is something like ' ', which is not
    equal to ''. Change str to repr and see better what item 6 is.

Working...