Convert numerical strings in a list to numerical (Integer/float) type-CodePudding

I have a list of mixed types of data:

list = ['Diff', '', '', 0, ' 16.67%', ' 2.81%', 0, ' 13.33%']

I only want to convert the numerical strings in this list to Integers/float, so my list will be:

newlist = ['Diff', '', '', 0,  16.67%,  2.81%, 0,  13.33%]

I know this res = [eval(i) for i in list] can convert all the strings to integers if everything in my list is numerical strings, but how do I do to only convert the numerical strings in a mixed-type list?

CodePudding user response：

This is one way of doing that by checking if the str isnumeric and type cast to int if it is a numeric value.

list = ['1', 'yes', 'diff', '43', '2', '4']

print(list)

for i, n in enumerate(list):
  if n.isnumeric():
    list[i] = int(n)

print(list)

CodePudding user response：

When doing type conversions in python, you attempt a conversion first and provide a reasonable fallback for the case it fails ("ask forgiveness, not permission"). There are just too many things that can go wrong with a conversion, and it's hard to check them all in advance.

def maybe_int(x):
    try:
        return int(x)
    except (TypeError, ValueError):
        return x


lst = ['1', 'yes', 'diff', '43', '2', '4']
print([maybe_int(x) for x in lst])

CodePudding user response：

I think you can use try-except:

for i in range(len(array)):
    try:
        array[i] = int(array[i])
    except:
        print("Can not cast this element to int") # you can write nothing here

More info about try-except here