java-intercept string substring and Substr__java

The way to intercept strings in Java is substring and substr, and the difference between them and their respective usage is specific. Now the summary is as follows: 1.substring method
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Definitions and usage

The substring method is used to extract characters from a string mediation between two specified subscripts.

Grammar

Stringobject.substring (Start,stop)

Parameter description

Start Required. A non-negative integer that stipulates the position of the first character of the substring to be extracted in the stringobject.

Stop is optional. A non-negative integer that is 1 more than the last character of the substring to extract in the Stringobject. If this argument is omitted, the returned substring continues to the end of the string.

return value

A new string that contains a substring of stringobject whose contents are all characters from the start to the stop-1, whose length is stop minus start.

Description

The substring returned by the substring method includes the character at start, but does not include the character at the end.

If start is equal to end, then the method returns an empty string (that is, a length of 0).

If start is larger than end, the method swaps the two parameters before extracting the substring.

If start or end is a negative number, it is replaced with 0.

2.substr method

Definitions and usage

The Substr method returns a substring of the specified length starting at the specified position.

Grammar

Stringobject.substr (start [, length])

Parameter description

Start Required. The starting position of the desired substring. The index of the first character in the string is 0.

Length is optional. The number of characters that should be included in the returned substring.

Description

If length is 0 or negative, an empty string is returned.

If this argument is not specified, the substring continues to the end of the stringobject.

Example:

var str = "0123456789";

Alert (str.substring (0));------------"0123456789"

Alert (str.substring (5));------------"56789"

alert (str.substring);-----------""

alert (str.substring);-----------""

Alert (str.substring ( -5));-----------"0123456789"

Alert (str.substring ( -10));----------"0123456789"

Alert (str.substring ( -12));----------"0123456789"

Alert (str.substring (0,5));----------"01234"

Alert (str.substring (0,10));---------"0123456789"

Alert (str.substring (0,12));---------"0123456789"

Alert (str.substring (2,0));----------"01"

Alert (str.substring (2,2));----------""

Alert (str.substring (2,5));----------"234"

Alert (str.substring (2,12));---------"23456789"

Alert (str.substring (2,-2));---------"01"

Alert (str.substring ( -1,5));---------"01234"

Alert (str.substring ( -1,-5));--------""

Alert (STR.SUBSTR (0));---------------"0123456789"

Alert (STR.SUBSTR (5));---------------"56789"

alert (STR.SUBSTR);--------------""

alert (STR.SUBSTR);--------------""

Alert (STR.SUBSTR ( -5));--------------"0123456789"

Alert (STR.SUBSTR ( -10));-------------"0123456789"

Alert (STR.SUBSTR ( -12));-------------"0123456789"

Alert (STR.SUBSTR (0,5));-------------"01234"

Alert (STR.SUBSTR (0,10));------------"0123456789"

Alert (STR.SUBSTR (0,12));------------"0123456789"

Alert (STR.SUBSTR (2,0));-------------""

Alert (STR.SUBSTR (2,2));-------------"23"

Alert (STR.SUBSTR (2,5));-------------"23456"

Alert (STR.SUBSTR (2,12));------------"23456789"

Alert (STR.SUBSTR (2,-2));------------""

Alert (STR.SUBSTR ( -1,5));------------"01234"

Alert (STR.SUBSTR ( -1,-5));-----------""