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:

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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:

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"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") # 1

If the element is not in the list, string or tuple, a ValueError will the thrown. For example:

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>>> "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:

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"string".find(substring)

"string".find(substring)

For example,

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"abc".find("b") # 1

"abc".find("b") # 1

If the substring is not in the string, then a -1 will be returned without errors.

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"abc".find("bac") # -1

"abc".find("bac") # -1

–EOF (The Ultimate Computing & Technology Blog) —