How to convert value of a String into it's specific datatype? '5' -> 5 OR 'a' -> a

Question

Consider I take a input as a python list and it contains values like ['1', '5', 't', 'John', '3.18']

How to convert every value into its specific data type?

Something like this

String '1' -> Integer 1

String 't' -> Char 't'

String '3.18' -> Float 3.18

Answer 1

Ask for forgiveness, not permission!

def to_type(x):
    try:
        return int(x)
    except ValueError:
        pass
    try:
        return float(x)
    except ValueError:
        pass
    return x

converted = [to_type(x) for x in your_list]

Answer 2

    values = ['1', '5', 't', 'John', '3.18']
    x=[int(value) if value.isdigit() else float(value) if value.replace('.', '', 1).isdigit() else value for value in values]
    print(x)

Output:
[1, 5, 't', 'John', 3.18]

1. If provided value is int it enters into if value.isdigit() and converts value into int.
2. if value is float then value.isdigit() is false and enters into if value.replace('.', '', 1).isdigit() where . will be replaced and verifies whether digit or not. If it is digits then converts into float.

Answer 3

The type of data in the values list is not clear, so there is a possibility of an unexpected error.

values = ['1', '5', 't', 'John', '3.18']

def change_type(value):
    if str(value).isdigit():
        return int(value)
    try:
        return float(value)
    except ValueError:
        return value

[change_type(value) for value in values]

[1, 5, 't', 'John', 3.18]

Answer 4

You can use try except structure to check whether an object can be converted to a specific data type:

l1 = ['1', '5', 't', 'John', '3.18']

#First object can be converted to int
try:
    l1[0] = int(l1[0])
except ValueError as e:
    print(e)

#Second one not
try:
    l1[2] = int(l1[2])
except ValueError as e:
    print(e)
    
print(l1)

In this case, the output would be:

invalid literal for int() with base 10: 't'
[1, '5', 't', 'John', '3.18']

You can use several checking using functions like int() , float() , bool() .... You may need to check the Python official documentation to see all possibilities.

Answer 5

try this:

a = "123"
b = int(a)

Answer 6

You could use the ast.literal_eval() function to parse the elements of the list the way the Python interpreter does. The code below would also work for tuples of strings.

from ast import literal_eval

def convert_seq(seq):
    """Return sequence of strings into one with each parsed as a literal value."""
    def convert_elem(elem):
        try:
            return literal_eval(elem)
        except ValueError:
            return elem
    return type(seq)(map(convert_elem, seq))

r = convert_seq(['1', '5', 't', 'John', '3.18', '"100"'])
print(r)  # -> [1, 5, 't', 'John', 3.18, '100']

Answer 7

try this:

def check_(x):
    if "." in x:
        new_x = x.replace(".","",1)
        if new_x.isdigit():
            xx= float(x)
            return "float",xx
    if x.isdigit():
            xx=int(x)
            return "int",xx
    else: 
        if len(x)>1:
            xx=x
            return "String",xx
        else:
            xx= x
            return "char",xx

var_ = "55.3"

print(check_(var_)[0])
print(check_(var_)[1])