Examples for string find in Python

Question

I am trying to find some examples but no luck. Anyone knows some examples on the net? I want to know what it returns when it can't find, and how to specify from start to end, which I guess is gonna be 0, -1.

Answer 1

I'm not sure what you're looking for, do you mean find()?

>>> x = "Hello World"
>>> x.find('World')
6
>>> x.find('Aloha');
-1

Answer 2

you can use str.index too:

>>> 'sdfasdf'.index('cc')
Traceback (most recent call last):
  File "<pyshell#144>", line 1, in <module>
    'sdfasdf'.index('cc')
ValueError: substring not found
>>> 'sdfasdf'.index('df')
1

Answer 3

find( sub[, start[, end]])

Return the lowest index in the string where substring sub is found, such that sub is contained in the range [start, end]. Optional arguments start and end are interpreted as in slice notation. Return -1 if sub is not found.

From the docs.

Answer 4

Honestly, this is the sort of situation where I just open up Python on the command line and start messing around:

 >>> x = "Dana Larose is playing with find()"
 >>> x.find("Dana")
 0
 >>> x.find("ana")
 1
 >>> x.find("La")
 5
 >>> x.find("La", 6)
 -1

Python's interpreter makes this sort of experimentation easy. (Same goes for other languages with a similar interpreter)

Answer 5

From here:

str.find(sub[, start[, end]])
Return the lowest index in the string where substring sub is found, such that sub is contained in the range [start, end]. Optional arguments start and end are interpreted as in slice notation. Return -1 if sub is not found."

So, some examples:

>>> str = "abcdefioshgoihgs sijsiojs "
>>> str.find('a')
0
>>> str.find('g')
10
>>> str.find('s',11)
15
>>> str.find('s',15)
15
>>> str.find('s',16)
17
>>> str.find('s',11,14)
-1