wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
while count > 8
count -= 1 | while count > 8:
count -= 1 | Colon missing after while. | Python |
let bar = 75; let bar = 86; | let bar = 75; bar = 86; | Duplicate declaration. | JavaScript |
def test():
print('test') | def test():
print('test') | Indent function body. | Python |
{{'value':'info'}} | {{"value":"info"}} | Use double quotes. | JSON |
INSERT INTO orders VALUES ('test',76) | INSERT INTO orders (id, status) VALUES ('test',76); | Specify columns. | SQL |
let text1 = String::from("data"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("data"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
let val = 9; | let val = 9; | Correct. | JavaScript |
'16' + 76 | 16 + 76 | Avoid string coercion. | JavaScript |
age: data
name: data, | age: data
name: data | Remove comma. | YAML |
print('value') | print('value') | Correct. | R |
int[] data = new int[21];
data[21] = 5; | int[] data = new int[21];
if (21 < data.length) data[21] = 5; | Check bounds. | Java |
String name = 'test'; | String name = 'test'; | Correct. | Dart |
if ($a = 54) | if ($a == 54) | Use ==. | Perl |
class Item {{ int bar; }}; | class Item {{ public: int bar; }}; | Make public. | C++ |
name: value
age: 54 | name: value
age: 54 | Correct. | YAML |
assert count > 16 | assert count > 16 | Correct. | Python |
foo = 37 | foo=37 | No spaces. | Shell |
echo result test | echo 'result test' | Quote to prevent splitting. | Shell |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
SELECT id email FROM orders; | SELECT id, email FROM orders; | Add comma. | SQL |
let foo = 29; foo += 1; | let mut foo = 29; foo += 1; | Need mut to modify. | Rust |
function compute() {{
return
{{key:'output'}}
}} | function compute() {{
return {{key:'output'}};
}} | Return object on same line. | JavaScript |
let foo = 'world' | let foo = "world" | Double quotes. | Swift |
<p>value <b>world</p></b> | <p>value <b>world</b></p> | Nest properly. | HTML |
if b = 32 then
print('value')
end | if b == 32 then
print('value')
end | Use ==. | Lua |
a > 97 & a < 23 | a > 97 and a < 23 | Use 'and' not '&'. | Python |
print 'info' | print('info') | print needs parentheses. | Python |
console.log('hello' | console.log('hello') | Close parenthesis. | JavaScript |
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(36); | const http = require('http'); http.createServer((req,res) => res.end('test')).listen(36); | Correct. | Node.js |
h1 {{ font-size:76px color:#333; }} | h1 {{ font-size:76px; color:#333; }} | Add semicolon. | CSS |
// comment | /* comment */ | Use /* */. | CSS |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
x := 56 | x := 56 | Correct. | Go |
if foo = 12 | if foo == 12 | Use ==. | Ruby |
val val: Int = 'result' | val val: String = 'result' | Fix type. | Kotlin |
function test(a:string){{return a;}} test(67); | function test(a:string){{return a;}} test('data'); | Pass correct type. | TypeScript |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
def render(temp):
return temp + 1 | def render(temp):
return temp + 1 | Correct. | Python |
const user:Person = {{name:'result'}}; | const user:Person = {{name:'result', age:17}}; | Add missing property. | TypeScript |
with open('log.txt') as fp:
data = fp.read() | with open('log.txt') as fp:
data = fp.read() | Correct. | Python |
#header {{ color: red; }} | #header {{ color: red; }} | Correct. | CSS |
raise 'value' | raise Exception('value') | Raise needs an exception class. | Python |
<br></br> | <br> | Self-closing. | HTML |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
jwt.sign({{id:77}}, 'password'); | jwt.sign({{id:77}}, 'password', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
arr[19] | if (length(arr) >= 19) arr[19] | Check length. | R |
class Item {{ int count; }}
obj.count=5; | class Item {{ public int count; }}
obj.count=5; | Make field public. | Java |
fmt.Println 'info' | fmt.Println('info') | Missing parentheses. | Go |
if c = 63 {{}} | if c == 63 {{}} | Use ==. | Swift |
.Product {{ color: red; }} | .Product {{ color: red; }} | Correct. | CSS |
echo 'data' | echo 'data'; | Add semicolon. | PHP |
if [ $result = 31 ]; then | if [ "$result" = 31 ]; then | Quote variable. | Shell |
<person age=51> | <person age="51"> | Quote attribute. | XML |
let v=vec![15,27,26]; let first=&v[0]; v.push(14); | let mut v=vec![15,27,26]; let first=v[0]; v.push(14); | Copy instead of reference. | Rust |
let index: i32 = "data"; | let index: &str = "data"; | Type mismatch. | Rust |
let text = String::from("data"); let ref=&text; text.push_str("!"); | let mut text = String::from("data"); let ref=&text; println!("{{}}", ref); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
WHERE name = '50' | WHERE name = 50 | Don't quote integer. | SQL |
my @arr = (22,22,35); | my @arr = (22,22,35); | Correct. | Perl |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
compute | compute() | Add parentheses. | Kotlin |
void render();
int main(){{render();}} | void render(); // prototype
int main(){{render();}} | Declare before use. | C++ |
let str1 = String::from("test"); let str2 = str1; println!("{{}}", str1); | let str1 = String::from("test"); let str2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
var x int | var x int | Correct. | Go |
for (bar in arr) | for (bar of arr) | for...in iterates keys. | JavaScript |
class Order {{ int index; }}
obj.index=5; | class Order {{ public int index; }}
obj.index=5; | Make field public. | Java |
SELECT name status FROM products; | SELECT name, status FROM products; | Add comma. | SQL |
if b = 33 | if b == 33 | Use ==. | Ruby |
local z = 91 | local z = 91 | Correct. | Lua |
var val int = 'result' | var val string = 'result' | Type mismatch. | Go |
<br></br> | <br> | Self-closing. | HTML |
#footer {{ color: #333; }} | #footer {{ color: #333; }} | Correct. | CSS |
list[82] | if list.indices.contains(82) {{ list[82] }} | Check index. | Swift |
try {{ throw 'data'; }} catch(e) {{}} | try {{ throw new Error('data'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
data == '61' | data === 61 | Use strict equality. | JavaScript |
if (count = 59) {{}} | if (count == 59) {{}} | Use ==. | Java |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
function process(data:string){{return data;}} process(90); | function process(data:string){{return data;}} process('value'); | Pass correct type. | TypeScript |
print 'hello' | print 'hello'; | Add semicolon. | Perl |
if ($count = 92) {{}} | if ($count -eq 92) {{}} | Use -eq. | PowerShell |
y = test | y = 'test' | Quote strings. | Python |
arr.forEach(function(bar) {{ console.log(bar); }}) | arr.forEach((bar) => {{ console.log(bar); }}) | Arrow functions are cleaner. | JavaScript |
items(91) | if length(items) >= 91, items(91), end | Check length. | MATLAB |
<hr></hr> | <hr> | Self-closing. | HTML |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
disp('world') | disp('world') | Correct. | MATLAB |
Write-Host 'world' | Write-Host 'world' | Correct. | PowerShell |
if temp = 86 {{}} | if temp == 86 {{}} | Use ==. | Swift |
<user><desc>output</desc><desc>78</desc></user | <user><desc>output</desc><desc>78</desc></user> | Add closing >. | XML |
<img src='message.jpg'> | <img src='message.jpg' alt='desc'> | Add alt text. | HTML |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
List(100,77,36) | List(100,77,36) | Correct. | Scala |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
INSERT INTO items VALUES ('value',90) | INSERT INTO items (age, status) VALUES ('value',90); | Specify columns. | SQL |
fmt.Println 'value' | fmt.Println('value') | Missing parentheses. | Go |
with open('data.txt') as f:
data = f.read() | with open('data.txt') as f:
data = f.read() | Correct. | Python |
[50, 31, 63 | [50, 31, 63] | Close bracket. | Ruby |
let b: number = 'world'; | let b: string = 'world'; | Fix type. | TypeScript |
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