There is a string, for example. EXAMPLE.

How can I remove the middle character, i.e., M from it? I don’t need the code. I want to know:

• Do strings in Python end in any special character?
• Which is a better way – shifting everything right to left starting from the middle character OR creation of a new string and not copying the middle character?

In Python, strings are immutable, so you have to create a new string. You have a few options of how to create the new string. If you want to remove the ‘M’ wherever it appears:

newstr = oldstr.replace("M", "")

If you want to remove the central character:

midlen = len(oldstr)/2   # //2 in python 3
newstr = oldstr[:midlen] + oldstr[midlen+1:]

You asked if strings end with a special character. No, you are thinking like a C programmer. In Python, strings are stored with their length, so any byte value, including \0, can appear in a string.

This is probably the best way:

original = "EXAMPLE"
removed = original.replace("M", "")

Don’t worry about shifting characters and such. Most Python code takes place on a much higher level of abstraction.

To replace a specific position:

s = s[:pos] + s[(pos+1):]

To replace a specific character:

s = s.replace('M','')

Strings are immutable. But you can convert them to a list, which is mutable, and then convert the list back to a string after you’ve changed it.

s = "this is a string"

l = list(s)  # convert to list

l[1] = ""    # "delete" letter h (the item actually still exists but is empty)
l[1:2] = []  # really delete letter h (the item is actually removed from the list)
del(l[1])    # another way to delete it

p = l.index("a")  # find position of the letter "a"
del(l[p])         # delete it

s = "".join(l)  # convert back to string

You can also create a new string, as others have shown, by taking everything except the character you want from the existing string.

How can I remove the middle character, i.e., M from it?

You can’t, because strings in Python are immutable.

Do strings in Python end in any special character?

No. They are similar to lists of characters; the length of the list defines the length of the string, and no character acts as a terminator.

Which is a better way – shifting everything right to left starting from the middle character OR creation of a new string and not copying the middle character?

You cannot modify the existing string, so you must create a new one containing everything except the middle character.

Use the translate() method:

>>> s = 'EXAMPLE'
>>> s.translate(None, 'M')
'EXAPLE'

UserString.MutableString

Mutable way:

import UserString

s = UserString.MutableString("EXAMPLE")

>>> type(s)
<type 'str'>

# Delete 'M'
del s[3]

# Turn it for immutable:
s = str(s)

card = random.choice(cards)
cardsLeft = cards.replace(card, '', 1)

How to remove one character from a string: Here is an example where there is a stack of cards represented as characters in a string. One of them is drawn (import random module for the random.choice() function, that picks a random character in the string). A new string, cardsLeft, is created to hold the remaining cards given by the string function replace() where the last parameter indicates that only one “card” is to be replaced by the empty string…

def kill_char(string, n): # n = position of which character you want to remove
    begin = string[:n]    # from beginning to n (n not included)
    end = string[n+1:]    # n+1 through end of string
    return begin + end
print kill_char("EXAMPLE", 3)  # "M" removed

I have seen this somewhere here.

Here’s what I did to slice out the “M”:

s = 'EXAMPLE'
s1 = s[:s.index('M')] + s[s.index('M')+1:]

If you want to delete/ignore characters in a string, and, for instance, you have this string,

“[11:L:0]”

from a web API response or something like that, like a CSV file, let’s say you are using requests

import requests
udid = 123456
url = 'http://webservices.yourserver.com/action/id-' + udid
s = requests.Session()
s.verify = False
resp = s.get(url, stream=True)
content = resp.content

loop and get rid of unwanted chars:

for line in resp.iter_lines():
  line = line.replace("[", "")
  line = line.replace("]", "")
  line = line.replace('"', "")

Optional split, and you will be able to read values individually:

listofvalues = line.split(':')

Now accessing each value is easier:

print listofvalues[0]
print listofvalues[1]
print listofvalues[2]

This will print

11

L

0

To delete a char or a sub-string once (only the first occurrence):

main_string = main_string.replace(sub_str, replace_with, 1)

NOTE: Here 1 can be replaced with any int for the number of occurrence you want to replace.

You can simply use list comprehension.

Assume that you have the string: my name is and you want to remove character m. use the following code:

"".join([x for x in "my name is" if x is not 'm'])

from random import randint


def shuffle_word(word):
    newWord=""
    for i in range(0,len(word)):
        pos=randint(0,len(word)-1)
        newWord += word[pos]
        word = word[:pos]+word[pos+1:]
    return newWord

word = "Sarajevo"
print(shuffle_word(word))

Another way is with a function,

Below is a way to remove all vowels from a string, just by calling the function

def disemvowel(s):
    return s.translate(None, "aeiouAEIOU")

Strings are immutable in Python so both your options mean the same thing basically.

What is the proper indentation for Python multiline strings within a function?

    def method():
        string = """line one
line two
line three"""

or

    def method():
        string = """line one
        line two
        line three"""

or something else?

It looks kind of weird to have the string hanging outside the function in the first example.

You probably want to line up with the """

def foo():
    string = """line one
             line two
             line three"""

Since the newlines and spaces are included in the string itself, you will have to postprocess it. If you don’t want to do that and you have a whole lot of text, you might want to store it separately in a text file. If a text file does not work well for your application and you don’t want to postprocess, I’d probably go with

def foo():
    string = ("this is an "
              "implicitly joined "
              "string")

If you want to postprocess a multiline string to trim out the parts you don’t need, you should consider the textwrap module or the technique for postprocessing docstrings presented in PEP 257:

def trim(docstring):
    if not docstring:
        return ''
    # Convert tabs to spaces (following the normal Python rules)
    # and split into a list of lines:
    lines = docstring.expandtabs().splitlines()
    # Determine minimum indentation (first line doesn't count):
    indent = sys.maxint
    for line in lines[1:]:
        stripped = line.lstrip()
        if stripped:
            indent = min(indent, len(line) - len(stripped))
    # Remove indentation (first line is special):
    trimmed = [lines[0].strip()]
    if indent < sys.maxint:
        for line in lines[1:]:
            trimmed.append(line[indent:].rstrip())
    # Strip off trailing and leading blank lines:
    while trimmed and not trimmed[-1]:
        trimmed.pop()
    while trimmed and not trimmed[0]:
        trimmed.pop(0)
    # Return a single string:
    return '\n'.join(trimmed)

The textwrap.dedent function allows one to start with correct indentation in the source, and then strip it from the text before use.

The trade-off, as noted by some others, is that this is an extra function call on the literal; take this into account when deciding where to place these literals in your code.

import textwrap

def frobnicate(param):
    """ Frobnicate the scrognate param.

        The Weebly-Ruckford algorithm is employed to frobnicate
        the scrognate to within an inch of its life.

        """
    prepare_the_comfy_chair(param)
    log_message = textwrap.dedent("""\
            Prepare to frobnicate:
            Here it comes...
                Any moment now.
            And: Frobnicate!""")
    weebly(param, log_message)
    ruckford(param)

The trailing \ in the log message literal is to ensure that line break isn’t in the literal; that way, the literal doesn’t start with a blank line, and instead starts with the next full line.

The return value from textwrap.dedent is the input string with all common leading whitespace indentation removed on each line of the string. So the above log_message value will be:

Prepare to frobnicate:
Here it comes...
    Any moment now.
And: Frobnicate!

Use inspect.cleandoc like so:

def method():
    string = inspect.cleandoc("""
        line one
        line two
        line three""")

Relative indentation will be maintained as expected. As commented below, if you want to keep preceding empty lines, use textwrap.dedent. However that also keeps the first line break.

Note: It’s good practice to indent logical blocks of code under its related context to clarify the structure. E.g. the multi-line string belonging to the variable string.

One option which seems to missing from the other answers (only mentioned deep down in a comment by naxa) is the following:

def foo():
    string = ("line one\n"          # Add \n in the string
              "line two"  "\n"      # Add "\n" after the string
              "line three\n")

This will allow proper aligning, join the lines implicitly, and still keep the line shift which, for me, is one of the reasons why I would like to use multiline strings anyway.

It doesn’t require any postprocessing, but you need to manually add the \n at any given place that you want the line to end. Either inline or as a separate string after. The latter is easier to copy-paste in.

Some more options. In Ipython with pylab enabled, dedent is already in the namespace. I checked and it is from matplotlib. Or it can be imported with:

from matplotlib.cbook import dedent

In documentation it states that it is faster than the textwrap equivalent one and in my tests in ipython it is indeed 3 times faster on average with my quick tests. It also has the benefit that it discards any leading blank lines this allows you to be flexible in how you construct the string:

"""
line 1 of string
line 2 of string
"""

"""\
line 1 of string
line 2 of string
"""

"""line 1 of string
line 2 of string
"""

Using the matplotlib dedent on these three examples will give the same sensible result. The textwrap dedent function will have a leading blank line with 1st example.

Obvious disadvantage is that textwrap is in standard library while matplotlib is external module.

Some tradeoffs here… the dedent functions make your code more readable where the strings get defined, but require processing later to get the string in usable format. In docstrings it is obvious that you should use correct indentation as most uses of the docstring will do the required processing.

When I need a non long string in my code I find the following admittedly ugly code where I let the long string drop out of the enclosing indentation. Definitely fails on “Beautiful is better than ugly.”, but one could argue that it is simpler and more explicit than the dedent alternative.

def example():
    long_string = '''\
Lorem ipsum dolor sit amet, consectetur adipisicing
elit, sed do eiusmod tempor incididunt ut labore et
dolore magna aliqua. Ut enim ad minim veniam, quis
nostrud exercitation ullamco laboris nisi ut aliquip.\
'''
    return long_string

print example()

If you want a quick&easy solution and save yourself from typing newlines, you could opt for a list instead, e.g.:

def func(*args, **kwargs):
    string = '\n'.join([
        'first line of very long string and',
        'second line of the same long thing and',
        'third line of ...',
        'and so on...',
        ])
    print(string)
    return

I prefer

    def method():
        string = \
"""\
line one
line two
line three\
"""

or

    def method():
        string = """\
line one
line two
line three\
"""

My two cents, escape the end of line to get the indents:

def foo():
    return "{}\n"\
           "freq: {}\n"\
           "temp: {}\n".format( time, freq, temp )

I came here looking for a simple 1-liner to remove/correct the identation level of the docstring for printing, without making it look untidy, for example by making it “hang outside the function” within the script.

Here’s what I ended up doing:

import string
def myfunction():

    """
    line 1 of docstring
    line 2 of docstring
    line 3 of docstring"""

print str(string.replace(myfunction.__doc__,'\n\t','\n'))[1:] 

Obviously, if you’re indenting with spaces (e.g. 4) rather than the tab key use something like this instead:

print str(string.replace(myfunction.__doc__,'\n    ','\n'))[1:]

And you don’t need to remove the first character if you like your docstrings to look like this instead:

    """line 1 of docstring
    line 2 of docstring
    line 3 of docstring"""

print string.replace(myfunction.__doc__,'\n\t','\n') 

The first option is the good one – with indentation included. It is in python style – provides readability for the code.

To display it properly:

print string.lstrip()

It depends on how you want the text to display. If you want it all to be left-aligned then either format it as in the first snippet or iterate through the lines left-trimming all the space.

For strings you can just after process the string. For docstrings you need to after process the function instead. Here is a solution for both that is still readable.

class Lstrip(object):
    def __rsub__(self, other):
        import re
        return re.sub('^\n', '', re.sub('\n$', '', re.sub('\n\s+', '\n', other)))

msg = '''
      Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod
      tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim
      veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea
      commodo consequat. Duis aute irure dolor in reprehenderit in voluptate
      velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat
      cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id
      est laborum.
      ''' - Lstrip()

print msg

def lstrip_docstring(func):
    func.__doc__ = func.__doc__ - Lstrip()
    return func

@lstrip_docstring
def foo():
    '''
    Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod
    tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim
    veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea
    commodo consequat. Duis aute irure dolor in reprehenderit in voluptate
    velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat
    cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id
    est laborum.
    '''
    pass


print foo.__doc__

I’m having a similar issue, code got really unreadable using multilines, I came out with something like

print("""aaaa
"""   """bbb
""")

yes, at beginning could look terrible but the embedded syntax was quite complex and adding something at the end (like ‘\n”‘) was not a solution

You can use this function trim_indent.

import re


def trim_indent(s: str):
    s = re.sub(r'^\n+', '', s)
    s = re.sub(r'\n+$', '', s)
    spaces = re.findall(r'^ +', s, flags=re.MULTILINE)
    if len(spaces) > 0 and len(re.findall(r'^[^\s]', s, flags=re.MULTILINE)) == 0:
        s = re.sub(r'^%s' % (min(spaces)), '', s, flags=re.MULTILINE)
    return s


print(trim_indent("""


        line one
            line two
                line three
            line two
        line one


"""))

Result:

"""
line one
    line two
        line three
    line two
line one
"""