clojure.string

by Stuart Sierra, Stuart Halloway, David Liebke

Full namespace name: clojure.string

Overview

Clojure String utilities

It is poor form to (:use clojure.string). Instead, use require
with :as to specify a prefix, e.g.

(ns your.namespace.here
  (:require [clojure.string :as str]))

Design notes for clojure.string:

1. Strings are objects (as opposed to sequences). As such, the
   string being manipulated is the first argument to a function;
   passing nil will result in a NullPointerException unless
   documented otherwise. If you want sequence-y behavior instead,
   use a sequence.

2. Functions are generally not lazy, and call straight to host
   methods where those are available and efficient.

3. Functions take advantage of String implementation details to
   write high-performing loop/recurs instead of using higher-order
   functions. (This is not idiomatic in general-purpose application
   code.)

4. When a function is documented to accept a string argument, it
   will take any implementation of the correct *interface* on the
   host platform. In Java, this is CharSequence, which is more
   general than String. In ordinary usage you will almost always
   pass concrete strings. If you are doing something unusual,
   e.g. passing a mutable implementation of CharSequence, then
   thread-safety is your responsibility.

Public Variables and Functions

blank?function

Usage: (blank? s)

True if s is nil, empty, or contains only whitespace.

Added in Clojure version 1.2

Source

capitalizefunction

Usage: (capitalize s)

Converts first character of the string to upper-case, all other
characters to lower-case.

Added in Clojure version 1.2

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ends-with?function

Usage: (ends-with? s substr)

True if s ends with substr.

Added in Clojure version 1.8

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escapefunction

Usage: (escape s cmap)

Return a new string, using cmap to escape each character ch
from s as follows:

If (cmap ch) is nil, append ch to the new string.
If (cmap ch) is non-nil, append (str (cmap ch)) instead.

Added in Clojure version 1.2

Source

includes?function

Usage: (includes? s substr)

True if s includes substr.

Added in Clojure version 1.8

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index-offunction

Usage: (index-of s value)
       (index-of s value from-index)

Return index of value (string or char) in s, optionally searching
forward from from-index. Return nil if value not found.

Added in Clojure version 1.8

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joinfunction

Usage: (join coll)
       (join separator coll)

Returns a string of all elements in coll, as returned by (seq coll),
separated by an optional separator.

Added in Clojure version 1.2

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last-index-offunction

Usage: (last-index-of s value)
       (last-index-of s value from-index)

Return last index of value (string or char) in s, optionally
searching backward from from-index. Return nil if value not found.

Added in Clojure version 1.8

Source

lower-casefunction

Usage: (lower-case s)

Converts string to all lower-case.

Added in Clojure version 1.2

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re-quote-replacementfunction

Usage: (re-quote-replacement replacement)

Given a replacement string that you wish to be a literal
replacement for a pattern match in replace or replace-first, do the
necessary escaping of special characters in the replacement.

Added in Clojure version 1.5

Source

replacefunction

Usage: (replace s match replacement)

Replaces all instance of match with replacement in s.

match/replacement can be:

string / string
char / char
pattern / (string or function of match).

See also replace-first.

The replacement is literal (i.e. none of its characters are treated
specially) for all cases above except pattern / string.

For pattern / string, $1, $2, etc. in the replacement string are
substituted with the string that matched the corresponding
parenthesized group in the pattern.  If you wish your replacement
string r to be used literally, use (re-quote-replacement r) as the
replacement argument.  See also documentation for
java.util.regex.Matcher's appendReplacement method.

Example:
(clojure.string/replace "Almost Pig Latin" #"\b(\w)(\w+)\b" "$2$1ay")
-> "lmostAay igPay atinLay"

Added in Clojure version 1.2

Source

replace-firstfunction

Usage: (replace-first s match replacement)

Replaces the first instance of match with replacement in s.

match/replacement can be:

char / char
string / string
pattern / (string or function of match).

See also replace.

The replacement is literal (i.e. none of its characters are treated
specially) for all cases above except pattern / string.

For pattern / string, $1, $2, etc. in the replacement string are
substituted with the string that matched the corresponding
parenthesized group in the pattern.  If you wish your replacement
string r to be used literally, use (re-quote-replacement r) as the
replacement argument.  See also documentation for
java.util.regex.Matcher's appendReplacement method.

Example:
(clojure.string/replace-first "swap first two words"
                              #"(\w+)(\s+)(\w+)" "$3$2$1")
-> "first swap two words"

Added in Clojure version 1.2

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reversefunction

Usage: (reverse s)

Returns s with its characters reversed.

Added in Clojure version 1.2

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splitfunction

Usage: (split s re)
       (split s re limit)

Splits string on a regular expression.  Optional argument limit is
the maximum number of splits. Not lazy. Returns vector of the splits.

Added in Clojure version 1.2

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split-linesfunction

Usage: (split-lines s)

Splits s on \n or \r\n.

Added in Clojure version 1.2

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starts-with?function

Usage: (starts-with? s substr)

True if s starts with substr.

Added in Clojure version 1.8

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trimfunction

Usage: (trim s)

Removes whitespace from both ends of string.

Added in Clojure version 1.2

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trim-newlinefunction

Usage: (trim-newline s)

Removes all trailing newline \n or return \r characters from
string.  Similar to Perl's chomp.

Added in Clojure version 1.2

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trimlfunction

Usage: (triml s)

Removes whitespace from the left side of string.

Added in Clojure version 1.2

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trimrfunction

Usage: (trimr s)

Removes whitespace from the right side of string.

Added in Clojure version 1.2

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upper-casefunction

Usage: (upper-case s)

Converts string to all upper-case.

Added in Clojure version 1.2

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