How to Find the Index of Given Element in String/Tuple/List in Python?
The index() in Python gives the lowest index that element matches the target. The index starts at zero – where the first element is at index 0. The syntax is:
1 2 3 | string.index(target) [list].index(target) (tuple).index(target) |
string.index(target) [list].index(target) (tuple).index(target)
As we can see, index() can be applied to both string, tuple and list. For example:
1 2 3 | "abcde".index("b") # 1 ["a","b","c","d","e"].index("b") # 1 ("a","b","c","d","e").index("b") # 1 |
"abcde".index("b") # 1
["a","b","c","d","e"].index("b") # 1
("a","b","c","d","e").index("b") # 1If the element is not in the list, string or tuple, a ValueError will the thrown. For example:
1 2 3 4 5 6 | >>> "find me".index("aaa") Traceback (most recent call last): File "<stdin>", line 1, in <module> ValueError: substring not found >>> </module> |
>>> "find me".index("aaa")
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ValueError: substring not found
>>>
</module>Therefore, it is often recommended to use index() if you are more likely to be sure that the substring exists or element appears in the tuple/list.
The find() in Python: Finding substring
The string object has a find() method which looks for the first appeared substring(). The Syntax is:
1 | "string".find(substring) |
"string".find(substring)
For example,
1 | "abc".find("b") # 1 |
"abc".find("b") # 1If the substring is not in the string, then a -1 will be returned without errors.
1 | "abc".find("bac") # -1 |
"abc".find("bac") # -1–EOF (The Ultimate Computing & Technology Blog) —
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