我如何从 python 中的字符串数字转换为 integer 数字

Question

I want to change type my string numbers. I wanna make them integer for comparing them which one is bigger.

numbers="4, 5, 29, 54, 4 ,0 ,-214, 542, -64, 1 ,-3, 6, -6"

ns=numbers.split()
nsi=[]
for i in range(len(ns)):
    ns[i]=int(ns[i])
    nsi.append(ns[i])


print(nsi)

I am getting error like this

ns[i]=int(ns[i])
ValueError: invalid literal for int() with base 10: '4,'

Answer 1

When you split the string it is split by whitespace... so with each number there is still the comma.

fixed:

numbers="4, 5, 29, 54, 4 ,0 ,-214, 542, -64, 1 ,-3, 6, -6"

ns=numbers.replace(",", "").split()
nsi=[]
for i in range(len(ns)):
    ns[i]=int(ns[i])
    nsi.append(ns[i])

print(nsi)
ns[i]=int(ns[i])

Answer 2

The issue is that split() uses a whitespace as default split character. So there is still the comma left. You are able to specify the separator for the function with split(', ') .

See this example on how split is used.

Answer 3

You can use different separator in split().

numbers="4, 5, 29, 54, 4 ,0 ,-214, 542, -64, 1 ,-3, 6, -6"

ns=numbers.split(sep=",")
nsi=[]
for i in range(len(ns)):
   ns[i]=int(ns[i])
   nsi.append(ns[i])

print(nsi)

Answer 4

You can do

numbers="4, 5, 29, 54, 4 ,0 ,-214, 542, -64, 1 ,-3, 6, -6"
ns = [int(i) for i in numbers.split(",")]
nsi=[]
for i in range(len(ns)):
   nsi.append(ns[i])
print(nsi)

or

numbers="4, 5, 29, 54, 4 ,0 ,-214, 542, -64, 1 ,-3, 6, -6"
ns = [int(i) for i in numbers.split(",")]
nsi=[]
nsi.extend(ns)
print(nsi)

That will cast all numbers in numbers list comperation to int's. Output

[4, 5, 29, 54, 4, 0, -214, 542, -64, 1, -3, 6, -6]

Answer 5

You made a mistake.

Change this line

ns=numbers.split()

Into this

ns=numbers.split(", ")

Answer 6

Using .split(", ") will give you an error when you try to convert the elements of the array into integers as numbers.split(", ") will give output as

ns = numbers.split(", ")
>>> print ns
['4', '5', '29', '54', '4 ,0 ,-214', '542', '-64', '1 ,-3', '6', '-6'] //'4 ->incorrect output
>>> print int(ns[4])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: invalid literal for int() with base 10: '4 ,0 ,-214'
>>>

Instead you can do only

numbers.split(",")

and it will give you the correct integer array. then typecast the elements for your purpose as int(...)

>>> ns = numbers.split(",")
>>> print ns
['4', ' 5', ' 29', ' 54', ' 4 ', '0 ', '-214', ' 542', ' -64', ' 1 ', '-3', ' 6', ' -6']
>>> a = int(ns[1])
>>> print a
5