Introduction to Python
Component of Python
RegEx stands for regular expression and it is the sequence of characters
that forms a search pattern means we can use it for checking if the particular string contains the specified search pattern.
Let's understand this by the following program :-
import re
txt = "Manish lives in India"
x = re.search("^Manish.*India$", txt)
if (x):
print("YES! We have a match!")
else:
print("No match")
So we can see our both “Manish” and “India” are in the string and it tells us the correct output.
We are having other set of functions too which allows us to search a string , which are describe as follows:-
| Function | Description |
|---|---|
| findall | Returns a list containing all matches |
| search | Returns a math object if there is a match anywhere in the string |
| split | Returns a list where the string has been split at each match |
| sub | Replaces one or many matches with a string |
findall() function
As we have discussed above also that the findall() function use to return a list containing all matches.
For ex:- Here in the below program we can find the occurrence of “es”
import re
str = "Manish is going to the market."
x = re.findall("is",str)
print(x)
Here it tells us that two times the “is” word is there in the string.
search() function
This function is use to search the string for a match. Let’s understand it by the following program :-
import re
str = "Manish is going to the market."
x = re.search("\s",str)
print("The first white-space character is located in position:", x.start())
So here like this we can search whatever we like in our string.
split function()
As we have discussed above also that split function use to split all the string characters.
import re
str = "Manish is going to the market."
x = re.split("\s",str)
print(x)
Here we can see whole string is splitted.
sub() function
As we know sub function() is use to replace one or many matches with a string.
Let’s understand this by the following program :-
import re
str = "Manish is going to the market."
x = re.sub("\s", "8",str)
print(x)
So like this we can replace.
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