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substring

extract a substring from a string

 

Calling Sequence

Parameters

Description

Thread Safety

Examples

Calling Sequence

substring(string, range, type)

Parameters

string

-

string or symbol

range

-

range m..n, or an integer m

type

-

optional, one of symbol, name, or string

Description

• 

The substring function extracts a substring from a string or symbol. By default, if applied to a string, a string is returned. If applied to a symbol, a symbol is returned.

• 

If a range is specified for range, and m and n evaluate to integers then substring will extract a substring from string starting with the mth character and ending with the nth character.

• 

Specifying a single integer m for range is equivalent to specifying the range m..m.

• 

Negative values for m and/or n stand for positions counted leftwards from the right end of the string.  The range 1..-1 refers to the entire string. The range -20..-1 refers to the last 20 characters of the string.

• 

If n is greater than the length of string then substring returns a string from the mth character to the end of string. If m is equal to n + 1 then substring returns the null string.

• 

If m is greater than the length of string then substring returns the null string.

• 

Zero values for m and/or n are not permitted, except for the case m = 1 and n = 0, which returns the null string as described above.

• 

If either m or n fails to evaluate to an integer, then substring remains unevaluated.

• 

The optional type argument specifies the type of value returned by substring. If type is one of the symbols symbol or name, then a symbol is always returned, even if the first argument was a string. If type is string, then a string is always returned, even if the first argument was a symbol.

Thread Safety

• 

The substring command is thread-safe as of Maple 15.

• 

For more information on thread safety, see index/threadsafe.

Examples

substringabcdefgh,3..7

cdefg

(1)

substringabcdefgh,5

e

(2)

substringabcdefgh,5..1

defgh

(3)

substringwxyz,2..2

x

(4)

substringabcdefgh,2..4,symbol

bcd

(5)

substringwxyz,2..3,string

xy

(6)

See Also

cat

length

searchtext

SearchText

selection

string

StringTools

StringTools[SubString]

symbol