How to use index in python

The index() method in Python detects whether the substring str is included in the string. If the beg (start) and end (end) ranges are specified, check whether it is included in the specified range. This method is the same as the python find() method. The same, except that if str is not in string, an exception will be reported.

Syntax

index() method syntax:

str.index(str, beg=0, end=len(string))

Parameters

str -- Specify the retrieved string beg -- Start index, default is 0. end – end index, defaults to the length of the string.

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Return value

If it contains a substring, return the starting index value , otherwise an exception is thrown.

Examples

The following examples show examples of the index() method:

#!/usr/bin/python
str1 = "this is string example....wow!!!";
str2 = "exam"; 
print str1.index(str2);
print str1.index(str2, 10);
print str1.index(str2, 40);

The output results of the above examples are as follows:

15
15
Traceback (most recent call last):
  File "test.py", line 8, in 
  print str1.index(str2, 40);
ValueError: substring not found

shell returned 1

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