I have a string school_name_1_class_2_city_name_3 want to split it to {school_name: 1, class:2, city_name: 3} in clojure I tried this code which didn't work
(def s "key_name_1_key_name_2")
(->> s
(re-seq #"(\w+)_(\d+)_")
(map (fn [[_ k v]] [(keyword k) (Integer/parseInt v)]))
(into {}))
You are looking for the ungreedy version of regex.
Try using #"(\w+?)_(\d+)_?" instead.
user=> (->> s (re-seq #"(\w+?)_(\d+)_?"))
(["key_name_1_" "key_name" "1"] ["key_name_2" "key_name" "2"])
When faced with a problem, just break it down and solve one small step at a time. Using let-spy-pretty from the Tupelo library allows us to see each step of the transformation:
(ns tst.demo.core
(:use tupelo.core tupelo.test)
(:require [clojure.string :as str]))
(defn str->keymap
[s]
(let-spy-pretty
[str1 (re-seq #"([a-zA-Z_]+|[0-9]+)" s)
seq1 (mapv first str1)
seq2 (mapv #(str/replace % #"^_+" "") seq1)
seq3 (mapv #(str/replace % #"_+$" "") seq2)
map1 (apply hash-map seq3)
map2 (tupelo.core/map-keys map1 #(keyword %) )
map3 (tupelo.core/map-vals map2 #(Long/parseLong %) )]
map3))
(dotest
(is= (str->keymap "school_name_1_class_2_city_name_3")
{:city_name 3, :class 2, :school_name 1}))
with result
------------------------------------
Clojure 1.10.3 Java 11.0.11
------------------------------------
Testing tst.demo.core
str1 =>
(["school_name_" "school_name_"]
["1" "1"]
["_class_" "_class_"]
["2" "2"]
["_city_name_" "_city_name_"]
["3" "3"])
seq1 =>
["school_name_" "1" "_class_" "2" "_city_name_" "3"]
seq2 =>
["school_name_" "1" "class_" "2" "city_name_" "3"]
seq3 =>
["school_name" "1" "class" "2" "city_name" "3"]
map1 =>
{"city_name" "3", "class" "2", "school_name" "1"}
map2 =>
{:city_name "3", :class "2", :school_name "1"}
map3 =>
{:city_name 3, :class 2, :school_name 1}
Ran 2 tests containing 1 assertions.
0 failures, 0 errors.
Passed all tests
Once you understand the steps and everything is working, just replace let-spy-pretty with let and continue on!
This was build using my favorite template project.
Given
(require '[clojure.string :as str])
(def s "school_name_1_class_2_city_name_3")
Following the accepted answer:
(->> s (re-seq #"(.*?)_(\d+)_?")
(map rest) ;; take only the rest of each element
(map (fn [[k v]] [k (Integer. v)])) ;; transform second as integer
(into {})) ;; make a hash-map out of all this
Or:
(apply hash-map ;; the entire thing as a hash-map
(interleave (str/split s #"_(\d+)(_|$)") ;; capture the names
(map #(Integer. (second %)) ;; convert to int
(re-seq #"(?<=_)(\d+)(?=(_|$))" s)))) ;; capture the integers
or:
(zipmap
(str/split s #"_(\d+)(_|$)") ;; extract names
(->> (re-seq #"_(\d+)(_|$)" s) ;; extract values
(map second) ;; by taking only second matched groups
(map #(Integer. %)))) ;; and converting them to integers
str/split leaves out the matched partsre-seq returns only the matched parts(_|$) ensures that the number is followed by a _ or is at an end positionThe least verbose (where (_|$) could be replaced by _?:
(->> (re-seq #"(.*?)_(\d+)(_|$)" s) ;; capture key vals
(map (fn [[_ k v]] [k (Integer. v)])) ;; reorder coercing values to int
(into {})) ;; to hash-map
