Round list of string/float if greater than x

Question

I wanted to see if there was a better way of doing the following:

I have a list of strings which may actually be floats, letters and other characters like "-" and "*":

mylist = ["34.59","0.32","-","39.29","E","0.13","*"]

I was to create a new list which iterates through mylist and checks IF an item is greater than 0.50, if it is, then that item should be rounded to the nearest whole number, if not, then it should be left alone and appended to the new list.

Here is what I have, this works but I wanted to know if there is a better way of doing it:

for item in mylist:
    try:
        num = float(item) 
        if num > 0.50:
            newlist.append(str(int(round(num))))
        else:
            newlist.append(item)
    except ValueError:
        newlist.append(item)

print newlist

Output:

['35', '0.32', '-', '39', 'E', '0.13', '*']

What do you guys thing?

Why do you want a better method? Is this method too slow? Does it take up too much memory? Or is it something else? — , Jul 24 '13 at 08:45

score 1 · Answer 1 · answered Jul 24 '13 at 08:55

If the values in your list can be separated by x[0].isdigit(), you can use a list comprehension. This means there will not be a '' or '2E' or '-3' or '.35' in your list.

>>> [str(int(round(float(x)))) if x[0].isdigit() and float(x) > 0.50 else x for x in mylist] 
['35', '0.32', '-', '39', 'E', '0.13', '*']
>>>

score 0 · Accepted Answer · answered Jul 24 '13 at 08:47

How about make a function?

def round_gt_05(x):
    try:
        num = float(x)
        if num > 0.5:
            return str(int(round(num)))
    except ValueError:
        pass
    return x

mylist = ["34.59","0.32","-","39.29","E","0.13","*"]
newlist = map(round_gt_05, mylist)
print newlist

score 0 · Answer 3 · answered Jul 24 '13 at 08:58

0

You could try this also.

def isfloatstring(instr):
    try:
         float(instr)
    except ValueError:
         return False
    return True


[str(int(round(float(n)))) if isfloatstring(n) and float(n) > 0.5 else n for n in listtemp]

answered Jul 24 '13 at 08:58

Karthikeyan

990
5
12

Round list of string/float if greater than x

3 Answers3