Removing an element from a string

I have a specific problem concerning strings. I have a string which has a dollar sign and sometimes a comma. Basically I am scraping a number with selenium and it can come in two forms:

1. $257,873 (with comma)

2. $257 (without comma)

How can I remove the comma only if there is one?

This is what I tried:

mc1 = (mc_txt.text).replace("$", "")

str = ""
for i in range(len(mc1)):
    if mc1[i] !=  ",":
        str = str + mc1[i]

mc = int(str)
print(mc)

The statment (mc_txt.text).replace("$", "") returns a string without any dollar signs. You can use the same trick to remove commas. In fact, since you are only trying to remove the leftmost dollar sign, a better option might be

mc = int(mc_txt.text.lstrip('$').replace(',', ''))

Here are a couple or examples using the REPL:

>>> '$123'.lstrip('$').replace(',', '')
'123'
>>> '$123,000'.lstrip('$').replace(',', '')
'123000'
>>> '123,000'.lstrip('$').replace(',', '')
'123000'
>>> '123'.lstrip('$').replace(',', '')
'123'