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PART II
C h a p t e r 2 2 :
S t r i n g s a n d F o r m a t t i n g
675
if(!str.Contains("powerful"))
Console.WriteLine("The sequence powerful was not found.");
}
}
The output is shown here:
The sequence power was found.
The sequence pow was found.
The sequence powerful was not found.
As the output shows,
Contains( )
searches for a matching sequence, not for whole words.
Thus, both “pow” and “power” are found. However, since there is no sequence that matches
“powerful”, it is (correctly) not found.
Several of the search methods have additional forms that allow you to begin a search
at a specified index or to specify a range to search within. All versions of the
String
search
methods are shown in Table 22-3.
Method
Description
public bool Contains(string
str
)
Returns true if the invoking string contains the string
specified by
str.
False is returned if
str
is not found.
public bool EndsWith(string
str
)
Returns true if the invoking string ends with the
string passed in
str.
Other wise, false is returned.
public bool
EndsWith(string
str
,
StringComparison
how
)
Returns true if the invoking string ends with the
string passed in
str.
Other wise, false is returned.
How the search is per formed is specified by
how
.
public bool
EndsWith(string
str
,
bool
ignoreCase
,
CultureInfo
ci
)
Returns true if the invoking string ends with the
string passed in
str.
Other wise, false is returned.
If
ignoreCase
is
true
, the search ignores case
differences. Other wise, case differences matter. The
search is conducted using the cultural information
passed in
ci.
public int IndexOf(char
ch
)
Returns the index of the first occurrence of
ch
within
the invoking string. Returns –1 if
ch
is not found.
public int IndexOf(string
str
)
Returns the index of the first occurrence of
str
within
the invoking string. Returns –1 if
str
is not found.
public int IndexOf(char
ch
, int
star t
)
Returns the index of the first occurrence of
ch
within
the invoking string. Searching begins at the index
specified by
star t.
Returns –1 if
ch
is not found.
public int IndexOf(string
str
, int
star t
)
Returns the index of the first occurrence of
str
within
the invoking string. Searching begins at the index
specified by
star t.
Returns –1 if
str
is not found.
T
ABLE
22-3
The Search Methods Offered by
String
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676
P a r t I I :
E x p l o r i n g t h e C # L i b r a r y
public int
IndexOf(char
ch
, int
star t
, int
count
)
Returns the index of the first occurrence of
ch
within
the invoking string. Searching begins at the index
specified by
star t
and runs for
count
elements.
Returns –1 if
ch
is not found.
public int
IndexOf(string
str
, int
star t
, int
count
)
Returns the index of the first occurrence of
str
within
the invoking string. Searching begins at the index
specified by
star t
and runs for
count
elements.
Returns –1 if
str
is not found.
public int IndexOf(string
str
,
StringComparison
how
)
Returns the index of the first occurrence of
str
within
the invoking string. How the search is per formed is
specified by
how.
Returns –1 if
str
is not found.
public int IndexOf(string
str
, int
star t
,
StringComparison
how
)
Returns the index of the first occurrence of
str
within
the invoking string. Searching begins at the index
specified by
star t.
How the search is per formed is
specified by
how
. Returns –1 if
str
is not found.
public int
IndexOf(string
str
, int
star t
, int
count
,
StringComparison
how
)
Returns the index of the first occurrence of
str
within
the invoking string. Searching begins at the index
specified by
star t
and runs for
count
elements.
How the search is per formed is specified by
how
.
Returns –1 if
ch
is not found.
public int LastIndexOf(char
ch
)
Returns the index of the last occurrence of
ch
within
the invoking string. Returns –1 if
ch
is not found.
public int LastIndexOf(string
str
)
Returns the index of the last occurrence of
str
within
the invoking string. Returns –1 if
str
is not found.
public int LastIndexOf(char
ch
, int
star t
)
Returns the index of the last occurrence of
ch
within
a range of the invoking string. The search proceeds
in reverse order, beginning at the index specified by
star t
and stopping at 0. Returns –1 if the
ch
is not
found.
public int LastIndexOf(string
str
, int
star t
)
Returns the index of the last occurrence of
str
within
a range of the invoking string. The search proceeds
in reverse order, beginning at the index specified
by
star t
and stopping at 0. Returns –1 if
str
is not
found.
public int
LastIndexOf(char
ch
, int
star t
,
int
count
)
Returns the index of the last occurrence of
ch
within
the invoking string. The search proceeds in reverse
order, beginning at the index specified by
star t
and
running for
count
elements. Returns –1 if
ch
is not
found.
T
ABLE
22-3
The Search Methods Offered by
String
(continued)
Method
Description
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