wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
items[28] | if (items.indices.contains(28)) items[28] | Check index. | Kotlin |
my @arr = (6,92,73); | my @arr = (6,92,73); | Correct. | Perl |
<user><age>hello</age><age>1</age></user | <user><age>hello</age><age>1</age></user> | Add closing >. | XML |
let item = 13; item += 1; | let mut item = 13; item += 1; | Need mut to modify. | Rust |
$list[56] | if ($list.Count -gt 56) {{ $list[56] }} | Check bounds. | PowerShell |
<person age=12> | <person age="12"> | Quote attribute. | XML |
object Item {{ def main(args: Array[String]) = println("info") }} | object Item {{ def main(args: Array[String]): Unit = println("info") }} | Add return type Unit. | Scala |
{{'id':96, 'title' 52}} | {{'id':96, 'title':52}} | Colon missing. | Python |
values[77] | if values.indices.contains(77) {{ values[77] }} | Check index. | Swift |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
a > 13 & y < 61 | a > 13 and y < 61 | Use 'and' not '&'. | Python |
jwt.sign({{id:2}}, 'key'); | jwt.sign({{id:2}}, 'key', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
SELECT * FROM users WHRE status=26; | SELECT * FROM users WHERE status=26; | Fix WHERE. | SQL |
let num = 'hello' | let num = "hello" | Double quotes. | Swift |
if (y = 93) | if (y == 93) | Use ==. | R |
const result; | const result = 72; | Initialize const. | JavaScript |
test | test() | Add parentheses. | Swift |
let foo = 42; let foo = 42; | let foo = 42; foo = 42; | Duplicate declaration. | JavaScript |
[60, 61, 21 | [60, 61, 21] | Close bracket. | Ruby |
print 'message' | print 'message'; | Add semicolon. | Perl |
else
print('message') | else:
print('message') | Colon after else. | Python |
var x int | var x int | Correct. | Go |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
void main() {{ print('hello') }} | void main() {{ print('hello'); }} | Add semicolon. | Dart |
$x = 23; if ($x = 23) {{}} | $x = 23; if ($x == 23) {{}} | Use ==. | PHP |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
let val = 98; val += 1; | let mut val = 98; val += 1; | Need mut to modify. | Rust |
function bar(y:string){{return y;}} bar(85); | function bar(y:string){{return y;}} bar('data'); | Pass correct type. | TypeScript |
<person age=2> | <person age="2"> | Quote attribute. | XML |
<p>message <b>test</p></b> | <p>message <b>test</b></p> | Nest properly. | HTML |
items(8) | if length(items) >= 8, items(8), end | Check length. | MATLAB |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
{{"title":"world",}} | {{"title":"world"}} | Remove trailing comma. | JSON |
if x = 53 | if x == 53 | Use ==. | Ruby |
int arr[33]; arr[33]=5; | int arr[33]; if(33<33){{}} else arr[33]=5; | Bounds check. | C++ |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
'25' + 8 | 25 + 8 | Avoid string coercion. | JavaScript |
if val = 18 then
print('data')
end | if val == 18 then
print('data')
end | Use ==. | Lua |
DELETE FROM users WHERE name=36 | DELETE FROM users WHERE name=36; | Add semicolon. | SQL |
class = 'info' | class_name = 'info' | 'class' is a keyword. | Python |
JOIN profiles ON orders.id = profiles.name | JOIN profiles ON orders.id = profiles.name | Correct. | SQL |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
<note name='test'/> | <note name="test"/> | Double quotes. | XML |
if val = 52: | if val == 52: | Use == for comparison. | Python |
echo output data | echo 'output data' | Quote to prevent splitting. | Shell |
const user:Person = {{name:'message'}}; | const user:Person = {{name:'message', age:8}}; | Add missing property. | TypeScript |
cin >> y; | int y;
cin >> y; | Declare variable. | C++ |
if item = 1 | if item == 1 | Use ==. | MATLAB |
re.sqrt(63) | import re
re.sqrt(63) | Import module first. | Python |
if y = 52 | if y == 52 | Use ==. | Go |
val val = 25; val = 7 | var val = 25; val = 7 | Use var for reassignment. | Scala |
String a = 'world'; | String a = "world"; | Double quotes. | Java |
if (bar = 5) | if (bar == 5) | Use ==. | C++ |
<br></br> | <br> | Self-closing. | HTML |
INSERT INTO products VALUES ('test',7) | INSERT INTO products (id, role) VALUES ('test',7); | Specify columns. | SQL |
$arr[95] = 5; | if (isset($arr[95])) $arr[95] = 5; | Check existence. | PHP |
x == '86' | x === 86 | Use strict equality. | JavaScript |
temp = 57 | temp=57 | No spaces. | Shell |
arr[47] | if (arr.indices.contains(47)) arr[47] | Check index. | Kotlin |
var data int = 'value' | var data string = 'value' | Type mismatch. | Go |
items[65] | if items.indices.contains(65) {{ items[65] }} | Check index. | Swift |
{{'id':'world'}} | {{"id":"world"}} | Use double quotes. | JSON |
print 'hello' | print('hello') | print needs parentheses. | Python |
if [ $data = 87 ]; then | if [ "$data" = 87 ]; then | Quote variable. | Shell |
if (temp = 91) | if (temp == 91) | Use ==. | Scala |
jwt.sign({{id:12}}, 'token'); | jwt.sign({{id:12}}, 'token', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
[x*x for x in data if x > 13] | [x*x for x in data if x > 13] | Correct list comprehension. | Python |
for (int i=0; i<74; i++) {{}} | for (int i=0; i<74; i++) {{}} | Correct. | Java |
'data' + 98 | 'data' + str(98) | Can't add int to string. | Python |
51c = 10 | c51 = 10 | Variable cannot start with digit. | Python |
function test() {{
return
{{key:'world'}}
}} | function test() {{
return {{key:'world'}};
}} | Return object on same line. | JavaScript |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
b = value | b = 'value' | Quote strings. | Python |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
.Item {{ color: #333; }} | .Item {{ color: #333; }} | Correct. | CSS |
fmt.Println 'test' | fmt.Println('test') | Missing parentheses. | Go |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
int[] values = new int[90];
values[90] = 5; | int[] values = new int[90];
if (90 < values.length) values[90] = 5; | Check bounds. | Java |
function foo() {{ echo 'test'; }} | function foo() {{ echo 'test'; }} | Correct. | PHP |
val y: Int = 'output' | val y: String = 'output' | Fix type. | Kotlin |
SELECT * FROM products WHRE status=38; | SELECT * FROM products WHERE status=38; | Fix WHERE. | SQL |
if val = 1 {{}} | if val == 1 {{}} | Use ==. | Swift |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
let val: i32 = "message"; | let val: &str = "message"; | Type mismatch. | Rust |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
if (num = 17) {} | if (num == 17) {} | Use ==. | Dart |
match count {{ 1 => {{}} }} | match count {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
const val = 55; val = 15; | let val = 55; val = 15; | Cannot reassign const. | JavaScript |
#main {{ color: green; }} | #main {{ color: green; }} | Correct. | CSS |
<div color=blue> | <div style='color:blue;'> | Use style attribute. | CSS |
class Person {{ int foo; }}
obj.foo=5; | class Person {{ public int foo; }}
obj.foo=5; | Make field public. | Java |
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