从字符串中删除特定字符

Question

I want to create a function that takes a line from a.txt file and remove double-spaces, but every thing i tried, and found on the internet, removes every instance of the character i want to remove or just the first instance.

    def reduceWhitespace():
        my_file = open("Teste.txt", "r")
        new_line = ""
        old_line = my_file.readline()
        empty_char = ""

        for char in range(len(old_line)):
            if old_line [char] == " ":
                if old_line [char + 1] == " ":
                    new_line = old_line.replace(old_line [char], empty_char)

        print (new_line)
        my_file.close()

    reduceWhitespace()

The output should be the line with no double-spaces:

"This line has extra space characters"

But instead it outputs the string with no spaces:

"Thislinehasextraspacecharacters"

Answer 1

below code will convert multiple space into one space: ( replace_double_space() function will convert multiple space in string into 1)

def replace_double_space(line):
    while "  " in line:
        line = line.replace("  ", " ")
    return line

my_file = open("Teste.txt", "r")
line = my_file.readline()
print ("before: ", line)

new_line = replace_double_space(line)
print ("after: ", new_line)

execution result:

PS E:\> python .\test.py
before:  This line has extra   space   characters
after:  This line has extra space characters

Answer 2

you can try something like this

x="aa//a//aa//aa/a//a"
x=x.replace("//","/",x.count("//"))
print(x)

output look like this: aa/a/aa/aa/a/a

Answer 3

You could use the built-in replace function. For example,

str = 'A  line with  single  and double spaces'
str = str.replace('  ', '')
print(str)

This would output 'Aline withsingleand double spaces' .

Answer 4

If you just replace them until done, you risk looping back through the line many times. Here is a generator based solution:

def singlespacer(s):
    last = None
    for c in s:
        if c == ' ' and last == ' ':
            continue
        last = c
        yield c
    
s = 'This  line  has       extra       spaces'

print (''.join(singlespacer(s)))