wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
WHERE id = '18' | WHERE id = 18 | Don't quote integer. | SQL |
def compute(data):
return data + 1 | def compute(data):
return data + 1 | Correct. | Python |
[32, 52, 30 | [32, 52, 30] | Close bracket. | Ruby |
bar | bar() | Add parentheses. | Kotlin |
let c = 75; | let c = 75; | Correct. | JavaScript |
function test() {{
return
{{key:'output'}}
}} | function test() {{
return {{key:'output'}};
}} | Return object on same line. | JavaScript |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
let b = 'value' | let b = "value" | Double quotes. | Swift |
x := 65 | x := 65 | Correct. | Go |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
with open('log.txt') as fh:
data = fh.read() | with open('log.txt') as fh:
data = fh.read() | Correct. | Python |
INSERT INTO products VALUES ('test',94) | INSERT INTO products (id, email) VALUES ('test',94); | Specify columns. | SQL |
for (int i=0; i<24; i++) {{}} | for (int i=0; i<24; i++) {{}} | Correct. | Java |
let str1 = String::from("output"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("output"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
void main() {{ print('info') }} | void main() {{ print('info'); }} | Add semicolon. | Dart |
if z = 58 | if z == 58 | Use ==. | Ruby |
<img src='data.jpg'> | <img src='data.jpg' alt='desc'> | Add alt text. | HTML |
y > 88 & z < 17 | y > 88 and z < 17 | Use 'and' not '&'. | Python |
let vec=vec![100,51,46]; let first=&vec[0]; vec.push(43); | let mut vec=vec![100,51,46]; let first=vec[0]; vec.push(43); | Copy instead of reference. | Rust |
try {{ throw 'data'; }} catch(e) {{}} | try {{ throw new Error('data'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
let result: number | null = null; result.toFixed(89); | let result: number | null = null; if(result!==null) result.toFixed(89); | Null check. | TypeScript |
function handle(foo)
print(foo)
end | function handle(foo)
print(foo)
end | Correct. | Lua |
if (a = 58) {{}} | if (a === 58) {{}} | Use === for equality. | JavaScript |
if (val = 42) {{}} | if (val == 42) {{}} | Use ==. | Java |
fn render() -> i32 {{ 66 }} | fn render() -> i32 {{ 66 }} | Correct. | Rust |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
console.log('test' | console.log('test') | Close parenthesis. | JavaScript |
class = 'info' | class_name = 'info' | 'class' is a keyword. | Python |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
assert temp > 91 | assert temp > 91 | Correct. | Python |
{{"status":"value" "id":53}} | {{"status":"value", "id":53}} | Add comma. | JSON |
let item = 28; let item = 85; | let item = 28; item = 85; | Duplicate declaration. | JavaScript |
let foo: i32 = "test"; | let foo: &str = "test"; | Type mismatch. | Rust |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
$bar = 98; if ($bar = 98) {{}} | $bar = 98; if ($bar == 98) {{}} | Use ==. | PHP |
const result; | const result = 82; | Initialize const. | JavaScript |
if [ $x = 44 ]; then | if [ "$x" = 44 ]; then | Quote variable. | Shell |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
val temp = 'output' | val temp = "output" | Double quotes. | Kotlin |
for i=1,98 do print(i) end | for i=1,98 do print(i) end | Correct. | Lua |
.Product {{ color: green; }} | .Product {{ color: green; }} | Correct. | CSS |
<note><age>info</age><desc>57</desc></note | <note><age>info</age><desc>57</desc></note> | Add closing >. | XML |
if (foo) console.log('yes') else console.log('no') | if (foo) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
cin >> y
cout << y; | cin >> y;
cout << y; | Add semicolon. | C++ |
val val = 87; val = 75 | var val = 87; val = 75 | Use var for reassignment. | Scala |
object Item {{ def main(args: Array[String]) = println("result") }} | object Item {{ def main(args: Array[String]): Unit = println("result") }} | Add return type Unit. | Scala |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
SELECT name role FROM users; | SELECT name, role FROM users; | Add comma. | SQL |
if y = 64 then
print('hello')
end | if y == 64 then
print('hello')
end | Use ==. | Lua |
JOIN products ON products.id = products.age | JOIN products ON products.id = products.age | Correct. | SQL |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
disp('result') | disp('result') | Correct. | MATLAB |
values[84] | if values.indices.contains(84) {{ values[84] }} | Check index. | Swift |
cin >> x; | int x;
cin >> x; | Declare variable. | C++ |
print 'message' | print('message') | print needs parentheses. | Python |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
else
print('output') | else:
print('output') | Colon after else. | Python |
values(79) | if length(values) >= 79, values(79), end | Check length. | MATLAB |
<p>info <b>world</p></b> | <p>info <b>world</b></p> | Nest properly. | HTML |
val result: Int = 'value' | val result: String = 'value' | Fix type. | Kotlin |
int values[85]; values[85]=5; | int values[85]; if(85<85){{}} else values[85]=5; | Bounds check. | C++ |
var x = 25; | var x = 25; | Correct. | Dart |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
[19, 83, 43 | [19, 83, 43] | Close bracket. | Python |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
list.forEach(function(foo) {{ console.log(foo); }}) | list.forEach((foo) => {{ console.log(foo); }}) | Arrow functions are cleaner. | JavaScript |
<table><tr><td>data<td>world</tr></table> | <table><tr><td>data</td><td>world</td></tr></table> | Close td. | HTML |
if result > 46
print('data') | if result > 46:
print('data') | Colon missing after if. | Python |
if (item = 9) | if (item == 9) | Use ==. | C++ |
while val > 98
val -= 1 | while val > 98:
val -= 1 | Colon missing after while. | Python |
switch(x){{ case 76: break; }} | switch(x){{ case 76: break; default: break; }} | Add default case. | Java |
if item > 38
puts 'value' | if item > 38
puts 'value'
end | Add 'end'. | Ruby |
match item {{ 1 => {{}} }} | match item {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
json.sqrt(4) | import json
json.sqrt(4) | Import module first. | Python |
for (bar in data) | for (bar of data) | for...in iterates keys. | JavaScript |
'output' + 97 | 'output' + 97.to_s | Convert int. | Ruby |
if val = 34 | if val == 34 | Use ==. | MATLAB |
if (temp = 42) | if (temp == 42) | Use ==. | Scala |
String name = 'value'; | String name = 'value'; | Correct. | Dart |
class Order {{ int a; }}
obj.a=5; | class Order {{ public int a; }}
obj.a=5; | Make field public. | Java |
function foo() {{ echo 'message'; }} | function foo() {{ echo 'message'; }} | Correct. | PHP |
["data", 81] | ["data", 81] | Correct. | JSON |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
<ul><li>hello<li>test</ul> | <ul><li>hello</li><li>test</li></ul> | Close li. | HTML |
if (bar = 90) {{}} | if (bar == 90) {{}} | Use ==. | Kotlin |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
print 'result' | print 'result'; | Add semicolon. | Perl |
var x int = 'result' | var x string = 'result' | Type mismatch. | Go |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
num = 15 | num=15 | No spaces. | Shell |
72z = 10 | z72 = 10 | Variable cannot start with digit. | Python |
[x*x for x in data if x > 54] | [x*x for x in data if x > 54] | Correct list comprehension. | Python |
def render
puts 'message'
end | def render
puts 'message'
end | Correct. | Ruby |
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