mapBully challenge

gudii9
gudii9 used Ask the Experts™
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Hi,

 I am working on below challenge
http://codingbat.com/prob/p197888


[/Map-1 > mapBully
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Modify and return the given map as follows: if the key "a" has a value, set the key "b" to have that value, and set the key "a" to have the value "". Basically "b" is a bully, taking the value and replacing it with the empty string.

mapBully({"b": "dirt", "a": "candy"}) → {"b": "candy", "a": ""}
mapBully({"a": "candy"}) → {"b": "candy", "a": ""}
mapBully({"b": "carrot", "c": "meh", "a": "candy"}) → {"b": "candy", "c": "meh", "a": ""}

how below got below result

mapBully({"a": "candy"}) → {"b": "candy", "a": ""}

there is no b in the input map right then how it came in the output map?
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Sr. Software engineer
Commented:
>> there is no b in the input map right then how it came in the output map?

It exactly does what is required:
Modify and return the given map as follows:
1) if the key "a" has a value, set the key "b" to have that value,
   {"a": "candy"}  == becomes ==> {"a": "candy", "b": "candy"}
2) and set the key "a" to have the value ""
   {"a": "candy", "b": "candy"}  == becomes ==> {"a": "", "b": "candy"}
mccarlIT Business Systems Analyst / Software Developer
Top Expert 2015
Commented:
there is no b in the input map right then how it came in the output map?

Because your code will add the "b" to the map

Author

Commented:
public Map<String, String> mapBully(Map<String, String> map) {
  String val=map.get("a");
  String backup=val;
  map.put("b",backup);
  map.put("a","");
  
  return map;
}

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failing two tests.
Expected      Run            
mapBully({"b": "dirt", "a": "candy"}) → {"b": "candy", "a": ""}      {"b": "candy", "a": ""}      OK      
mapBully({"a": "candy"}) → {"b": "candy", "a": ""}      {"b": "candy", "a": ""}      OK      
mapBully({"b": "carrot", "c": "meh", "a": "candy"}) → {"b": "candy", "c": "meh", "a": ""}      {"b": "candy", "c": "meh", "a": ""}      OK      
mapBully({"b": "carrot"}) → {"b": "carrot"}      {"b": null, "a": ""}      X      
mapBully({"c": "meh"}) → {"c": "meh"}      {"b": null, "c": "meh", "a": ""}      X      
mapBully({"c": "meh", "a": "sparkle"}) → {"b": "sparkle", "c": "meh", "a": ""}      {"b": "sparkle", "c": "meh", "a": ""}      OK      
please advise

Author

Commented:
public Map<String, String> mapBully(Map<String, String> map) {
  if(map.containsKey("a")){
  String val=map.get("a");
  String backup=val;
  map.put("b",backup);
  map.put("a","");
  }
  return map;
}

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above passes all tests. any improvements or alternate approaches?
zzynxSr. Software engineer

Commented:
>> any improvements
Yes.
1. Indent your code decently
2. There's no need to work with those temporary variables

public Map<String, String> mapBully(Map<String, String> map) {
    if (map.containsKey("a")) {
       map.put("b", map.get("a"));
       map.put("a","");
    }
    return map;
}

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And you could have seen the code in the above post if you'd simply clicked the "Show Solution" button next to the "Go" button on the codingbat webpage you linked to.

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