如何从字符串中删除字符？

Question

I'm a beginner in python and i started to learn python 3 without learning python 2. I'm trying to apply the string.translate() function which I've learnt that is not supported in python 3.

from string import maketrans


intab = "0123456789"
outtab = ""
trantab = maketrans(intab, outtab)
str = "p1y2t3h4o5n6"
print(str.translate(trantab))

running it gives following error:

Traceback (most recent call last):
  File "C:\Users\Nahid\Desktop\test.py", line 1, in <module>
from string import maketrans
ImportError: cannot import name 'maketrans'

I intend to get the output as python . How can I do that?

Answer 1

请改用str.maketrans静态方法（请注意，您无需导入它）。

Answer 2

Answer to the question

Don't use the name str for your string variable. It will mask the built-in str :

intab = "0123456789"
outtab = intab[::-1]
trantab = str.maketrans(intab, outtab)
mystring = "p1y2t3h4o5n6"
print(mystring.translate(trantab))

Output:

p8y7t6h5o4n3

Your intab and outtab must have the same length. Most functions from string in Python 2 became methods of str for a while in Python 2 and were dropped as functions from string in Python 3. So use str.maketrans() .

Solving the problem

If want to remove characters from a string you can do:

remove = set("0123456789")
mystring = "p1y2t3h4o5n6"
print(''.join(x for x in mystring if x not in remove))

Output:

python

If you want to remove numbers you can also do:

print(''.join(x for x in mystring if not x.isdigit()))

Output:

python

Answer 3

As already mentioned in from Python 3.x you need to use the static method str.maketrans . That being said the intab and outtab must have equal length.

>>> str = "p1y2t3h4o5n6"
>>> intab = "0123456789"
>>> outtab = " "
>>> trantab = str.maketrans(intab, outtab * len(intab))
>>> print(mystring.translate(trantab).replace(" ", ""))
python

But you can also do this using regular expression

>>> import re
>>> re.sub(r'[0-9]', '', mystring)
'python'