I created function for replace string with dictionary,
def tolower(text):
patterns = {
"\[(.*?)\]": (r"[\1-123]").lower()
}
for key in patterns:
text = re.sub(key, patterns[key], text)
return text
print tolower("[IMG]UPPER[/IMG]")
But I want python backreference \1 convert the string to lower after replace.
So, I'm expecting the result like this :
[img-123]UPPER[/img-123]
Can someone please tell me how it's working with replacing regex backreference?
You can pass a function to re.sub() that will allow you to do this, here is an example:
def replaceLower(match):
return '[' + match.group(1).lower() + '-123]'
To use it, instead of having each key map to a regular expression, map the key to a function that is called by re.sub:
def tolower(text):
patterns = {
"\[(.*?)\]": replaceLower
}
for key in patterns:
text = re.sub(key, patterns[key], text)
return text
Change to using a callable as the replacement argument:
import re
def tolower(text):
patterns = {
"\[(.*?)\]": lambda m: '[{}-123]'.format(m.group(1).lower())
}
for key in patterns:
text = re.sub(key, patterns[key], text)
return text
print(tolower("[IMG]UPPER[/IMG]"))
# [img-123]UPPER[/img-123]
