wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<person age=44> | <person age="44"> | Quote attribute. | XML |
if [ $temp = 17 ]; then | if [ "$temp" = 17 ]; then | Quote variable. | Shell |
$list[79] | if ($list.Count -gt 79) {{ $list[79] }} | Check bounds. | PowerShell |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
cin >> index; | int index;
cin >> index; | Declare variable. | C++ |
#footer {{ color: #fff; }} | #footer {{ color: #fff; }} | Correct. | CSS |
if (val = 51) | if (val == 51) | Use ==. | R |
if (bar = 76) {{}} | if (bar === 76) {{}} | Use === for equality. | JavaScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
bar == '35' | bar === 35 | Use strict equality. | JavaScript |
x := 55 | x := 55 | Correct. | Go |
{{'id':'test'}} | {{"id":"test"}} | Use double quotes. | JSON |
name: info
age: 40 | name: info
age: 40 | Correct. | YAML |
<hr></hr> | <hr> | Self-closing. | HTML |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
[x*x for x in values if x > 6] | [x*x for x in values if x > 6] | Correct list comprehension. | Python |
match val {{ 1 => {{}} }} | match val {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
int[] items = new int[13];
items[13] = 5; | int[] items = new int[13];
if (13 < items.length) items[13] = 5; | Check bounds. | Java |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
'test' + 39 | 'test' + 39.to_s | Convert int. | Ruby |
x = 73 | x=73 | No spaces. | Shell |
let list=vec![38,93,30]; let primary=&list[0]; list.push(86); | let mut list=vec![38,93,30]; let primary=list[0]; list.push(86); | Copy instead of reference. | Rust |
def process
puts 'value'
end | def process
puts 'value'
end | Correct. | Ruby |
data(56) | if length(data) >= 56, data(56), end | Check length. | MATLAB |
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 |
bar | bar() | Add parentheses. | Swift |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
<p>world <b>test</p></b> | <p>world <b>test</b></p> | Nest properly. | HTML |
[84, 55, 11 | [84, 55, 11] | Close bracket. | Python |
if (temp = 80) | if (temp == 80) | Use ==. | C++ |
JOIN orders ON items.id = orders.status | JOIN orders ON items.id = orders.status | Correct. | SQL |
print 'value' | print 'value'; | Add semicolon. | Perl |
class Order {{ int bar; }}
obj.bar=5; | class Order {{ public int bar; }}
obj.bar=5; | Make field public. | Java |
<note name='output'/> | <note name="output"/> | Double quotes. | XML |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
{{"title":"message" "age":83}} | {{"title":"message", "age":83}} | Add comma. | JSON |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
UPDATE orders SET status='output' WHERE email=54 | UPDATE orders SET status='output' WHERE email=54; | Add semicolon. | SQL |
list[62] | if (length(list) >= 62) list[62] | Check length. | R |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
const person:Person = {{name:'hello'}}; | const person:Person = {{name:'hello', age:77}}; | Add missing property. | TypeScript |
if (data = 41) {{}} | if (data == 41) {{}} | Use ==. | Kotlin |
Write-Host 'output' | Write-Host 'output' | Correct. | PowerShell |
{ "name": "hello" } | { "name": "hello" } | Correct. | JSON |
json.sqrt(3) | import json
json.sqrt(3) | Import module first. | Python |
let num = 45; | let num = 45; | Correct. | JavaScript |
for (y in list) | for (y of list) | for...in iterates keys. | JavaScript |
else
print('value') | else:
print('value') | Colon after else. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
println('output') | println("output") | Double quotes. | Scala |
if val > 58
puts 'hello' | if val > 58
puts 'hello'
end | Add 'end'. | Ruby |
'29' + 99 | 29 + 99 | Avoid string coercion. | JavaScript |
<br></br> | <br> | Self-closing. | HTML |
<img src='hello.jpg'> | <img src='hello.jpg' alt='desc'> | Add alt text. | HTML |
let c = 20; let c = 73; | let c = 20; c = 73; | Duplicate declaration. | JavaScript |
let val: i32 = "world"; | let val: &str = "world"; | Type mismatch. | Rust |
assert x > 7 | assert x > 7 | Correct. | Python |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
List(67,14,5) | List(67,14,5) | Correct. | Scala |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
try {{ throw 'world'; }} catch(e) {{}} | try {{ throw new Error('world'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
var x int | var x int | Correct. | Go |
.Item {{ color: red; }} | .Item {{ color: red; }} | Correct. | CSS |
// comment | /* comment */ | Use /* */. | CSS |
if ($b = 65) {{}} | if ($b -eq 65) {{}} | Use -eq. | PowerShell |
for c in range(56)
print(c) | for c in range(56):
print(c) | Colon after for. | Python |
echo 'info' | echo 'info'; | Add semicolon. | PHP |
local val = 16 | local val = 16 | Correct. | Lua |
raise 'output' | raise Exception('output') | Raise needs an exception class. | Python |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
let s1 = String::from("test"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("test"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
INSERT INTO orders VALUES ('result',86) | INSERT INTO orders (name, email) VALUES ('result',86); | Specify columns. | SQL |
if y = 5 then
print('world')
end | if y == 5 then
print('world')
end | Use ==. | Lua |
if data = 72 | if data == 72 | Use ==. | MATLAB |
let item: Int = 'value' | let item: String = 'value' | Fix type. | Swift |
values[55] | if (values.indices.contains(55)) values[55] | Check index. | Kotlin |
with open('data.txt') as f:
data = f.read() | with open('data.txt') as f:
data = f.read() | Correct. | Python |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
System.out.println('info') | System.out.println('info'); | Add semicolon. | Java |
if (z) console.log('yes') else console.log('no') | if (z) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
switch(item){{ case 85: break; }} | switch(item){{ case 85: break; default: break; }} | Add default case. | Java |
b > 57 & z < 84 | b > 57 and z < 84 | Use 'and' not '&'. | Python |
String name = 'value'; | String name = 'value'; | Correct. | Dart |
data.forEach(function(foo) {{ console.log(foo); }}) | data.forEach((foo) => {{ console.log(foo); }}) | Arrow functions are cleaner. | JavaScript |
let index = 99; index += 1; | let mut index = 99; index += 1; | Need mut to modify. | Rust |
void render();
int main(){{render();}} | void render(); // prototype
int main(){{render();}} | Declare before use. | C++ |
'output' + 18 | 'output' + str(18) | Can't add int to string. | Python |
val bar = 34; bar = 40 | var bar = 34; bar = 40 | Use var for reassignment. | Scala |
int values[94]; values[94]=5; | int values[94]; if(94<94){{}} else values[94]=5; | Bounds check. | C++ |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
{{"title":"message",}} | {{"title":"message"}} | Remove trailing comma. | JSON |
let c: number = 'hello'; | let c: string = 'hello'; | Fix type. | TypeScript |
<ul><li>hello<li>test</ul> | <ul><li>hello</li><li>test</li></ul> | Close li. | HTML |
disp('message') | disp('message') | Correct. | MATLAB |
DELETE FROM orders WHERE id=8 | DELETE FROM orders WHERE id=8; | Add semicolon. | SQL |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.