CODEWITHSUNDEEP
pythonstringintegernumbersconverters
kabil
kabil

Reputation: 51

How to convert string to number in python?

I have list of numbers as str

li = ['1', '4', '8.6']

if I use int to convert the result is [1, 4, 8]. If I use float to convert the result is [1.0, 4.0, 8.6]

I want to convert them to [1, 4, 8.6]

I've tried this:

li = [1, 4, 8.6]
intli = list(map(lambda x: int(x),li))
floatli = list(map(lambda x: float(x),li))
print(intli)
print(floatli)

>> [1, 4, 8]
>> [1.0, 4.0, 8.6]

Upvotes: 3

Views: 20107

Answers (5)

Arifa Chan
Arifa Chan

Reputation: 1017

You can try map each element using loads from json:

from json import loads
li = ['1', '4', '8.6']
li = [*map(loads,li)]
print(li)

# [1, 4, 8.6]

Or using eval():

print(li:=[*map(eval,['1','4','8.6','-1','-2.3'])])

# [1, 4, 8.6, -1, -2.3]

Notes:

Using json.loads() or ast.literal_eval is safer than eval() when the string to be evaluated comes from an unknown source

Upvotes: 0

gog
gog

Reputation: 11347

You're going to need a small utility function:

def to_float_or_int(s):
    n = float(s)
    return int(n) if n.is_integer() else n

Then,

result = [to_float_or_int(s) for s in li]

Upvotes: 1

Amir reza Riahi
Amir reza Riahi

Reputation: 2460

You can use ast.literal_eval to convert an string to a literal:

from ast import literal_eval

li = ['1', '4', '8.6']
numbers = list(map(literal_eval, li))

As @Muhammad Akhlaq Mahar noted in his comment, str.isidigit does not return True for negative integers:

>>> '-3'.isdigit()
False

Upvotes: 1

Aivar Paalberg
Aivar Paalberg

Reputation: 5167

One way is to use ast.literal_eval

>>> from ast import literal_eval
>>> spam = ['1', '4', '8.6']
>>> [literal_eval(item) for item in spam]
[1, 4, 8.6]

Word of caution - there are values which return True with str.isdigit() but not convertible to int or float and in case of literal_eval will raise SyntaxError.

>>> '1²'.isdigit()
True

Upvotes: 1

Lexpj
Lexpj

Reputation: 1083

Convert the items to a integer if isdigit() returns True, else to a float. This can be done by a list generator:

li = ['1', '4', '8.6']
lst = [int(x) if x.isdigit() else float(x) for x in li]
print(lst)

To check if it actually worked, you can check for the types using another list generator:

types = [type(i) for i in lst]
print(types)

Upvotes: 8

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