Finding and replacing
Regular Expressions in Python
Maria Eugenia Inzaugarat
Data scientist
Finding substrings
- Search target string for a specified substring.
my_string = "Where's Waldo?"
my_string.find("Waldo")
8
my_string.find("Wenda")
-1
Finding substrings
- Search target string for a specified substring.
my_string = "Where's Waldo?"
my_string.find("Waldo", 0, 6)
-1
Index function
- Similar to
.find(), search target string for a specified substring.
my_string = "Where's Waldo?"
my_string.index("Waldo")
8
my_string.index("Wenda")
File "<stdin>", line 1, in <module>
ValueError: substring not found
Index function
- Similar to
.find(), search target string for a specified substring.
my_string = "Where's Waldo?"
try:
my_string.index("Wenda")
except ValueError:
print("Not found")
"Not found"
Counting occurrences
- Return number of occurrences for a specified substring.
my_string = "How many fruits do you have in your fruit basket?"
my_string.count("fruit")
2
my_string.count("fruit", 0, 16)
1
Replacing substrings
- Replace occurrences of substring with new substring.
my_string = "The red house is between the blue house and the old house"
print(my_string.replace("house", "car"))
The red car is between the blue car and the old car
print(my_string.replace("house", "car", 2))
The red car is between the blue car and the old house
