WolframLang: String

Quote String

String is quoted by double straight quote.

"this is a string"

string can be multi-line, can include any unicode characters:

x = "i ♥ cats
and dogs"

String Escapes

\n

newline char in string.

\t

tab char in string.

\"

double quote in string.

example:

"this is\na string"

"Said \"Yes\""

length

StringLength

return the number of chars. StringLength

StringLength["abc"]
(* 3 *)

join string

StringJoin[s1, s2]

Short syntax: s1 <> s2
StringJoin

StringJoin["ab", "cd", "e"]
(* "abcde" *)

"ab" <> "cd" <> "e"
(* "abcde" *)

Get Substring, by Position

StringTake[str, n]

first char to nth. StringTake

StringTake["abcde", 3] === "abc"

StringTake[str, -n]

count from right, first char to nth.

StringTake["abcde", -3] === "cde"

StringTake[str, {n}]

nth char.

StringTake["abcde", {3}] === "c"

StringTake[str, {n, m}]

nth to mth chars.

StringTake["abcde", {2,4}] === "bcd"

StringTake[str, {spec1, spec2 etc}]

return a list of result, for each spec.

StringTake["abcde", {2, {2}, {2,4}}] === {"ab", "b", "bcd"}

StringTake[{str1, str2 etc}, spec]

return a list of result, for each string.

StringTake[{"abcde", "123456"}, 2] === {"ab", "12"}
StringTake[{"abcde", "123456"}, {2}] === {"b", "2"}
StringTake[{"abcde", "123456"}, {2,4}] === {"bcd", "234"}

StringTake[{"abcde", "123456"}, {2, {2}, {2,4}}] ===
{{"ab", "b", "bcd"}, {"12", "2", "234"}}

Get Substring by Pattern

StringCases

Get substring, by String pattern (regex) . Return a List . Use Part to get the elements. StringCases

(* extract email address *)

x = "text contain emails john@gmail.com and mary441@yahoo.com etc";

StringCases[ x, RegularExpression[ "[a-z0-9]+@[a-z0-9]+\\.com" ] , IgnoreCase -> True]

(* {"john@gmail.com", "mary441@yahoo.com"} *)

String to list

StringSplit

split a string to a list of strings. StringSplit

(* split by whitespace *)
StringSplit[ "a b" ]
(* {"a", "b"} *)

(* split by comma *)
StringSplit[ "a,b,c", "," ]
(* {"a", "b", "c"} *)

List to string

StringRiffle

List to string. StringRiffle

StringRiffle[ {"a" , "b" , "c"}, " " ]
 (* "a b c" *)

Insert into string

StringInsert

Insert by position StringInsert

StringInsert[ "love cat", "I ", 1 ]
(* I love cat *)

delete substring

StringDrop

Delete parts by position. StringDrop

StringDelete

Delete parts by String pattern (regex) . StringDelete

StringTrim

Remove whitespace StringTrim

search, test, pattern matching

Note: function name that ends in Q means it always return one of the builtin symbols True or False. Q is a reminder for “Question”. [see WolframLang: True/False (boolean)]

Many of the following function takes a String pattern (regex) .

StringQ

Check if is string. StringQ

StringStartsQ

StringStartsQ

StringEndsQ

StringEndsQ

StringMatchQ

StringMatchQ

StringContainsQ

StringContainsQ[ "some thing", "th" ]
(* True *)

StringContainsQ

StringFreeQ

StringFreeQ

StringPosition

StringPosition

StringCount

Count occurance StringCount

string replace

StringReplace

replace string by String pattern (regex) . StringReplace

StringReplace[ "some dogs" , {"dog" -> "cat"}]

(* "some cats" *)

StringReplacePart

replace string by position. StringReplacePart

StringReplacePart[ "some dogs", "cat", {6, 8}]
(* "some cats" *)

format string

ToString

Convert number or any expression to string. ToString

StringTemplate

Template system with placeholders StringTemplate