wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
{{'age':76, 'id' 73}} | {{'age':76, 'id':73}} | Colon missing. | Python |
'output' + 69 | 'output' + 69.to_s | Convert int. | Ruby |
JOIN products ON users.id = products.id | JOIN products ON users.id = products.id | Correct. | SQL |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
for (temp in values) | for (temp of values) | for...in iterates keys. | JavaScript |
let c: number | null = null; c.toFixed(35); | let c: number | null = null; if(c!==null) c.toFixed(35); | Null check. | TypeScript |
INSERT INTO products VALUES ('value',2) | INSERT INTO products (id, email) VALUES ('value',2); | Specify columns. | SQL |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
class User {{ int foo; }}; | class User {{ public: int foo; }}; | Make public. | C++ |
c = 35 | c=35 | No spaces. | Shell |
.Product {{ color: #333; }} | .Product {{ color: #333; }} | Correct. | CSS |
name: info
value: world, | name: info
value: world | Remove comma. | YAML |
var x = 57; | var x = 57; | Correct. | Dart |
String count = 'info'; | String count = "info"; | Double quotes. | Java |
if ($foo = 14) | if ($foo == 14) | Use ==. | Perl |
if (c = 37) | if (c == 37) | Use ==. | Scala |
let x: i32 = "result"; | let x: &str = "result"; | Type mismatch. | Rust |
let str1 = String::from("world"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("world"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
let val = 'info' | let val = "info" | Double quotes. | Swift |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
{{"id":"value",}} | {{"id":"value"}} | Remove trailing comma. | JSON |
$z = 44; if ($z = 44) {{}} | $z = 44; if ($z == 44) {{}} | Use ==. | PHP |
[26, 11, 87 | [26, 11, 87] | Close bracket. | Ruby |
a > 39 & z < 44 | a > 39 and z < 44 | Use 'and' not '&'. | Python |
#header {{ color: red; }} | #header {{ color: red; }} | Correct. | CSS |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
def compute(y):
return y + 1 | def compute(y):
return y + 1 | Correct. | Python |
let temp = 15; | let temp = 15; | Correct. | JavaScript |
while data > 20
data -= 1 | while data > 20:
data -= 1 | Colon missing after while. | Python |
switch(val){{ case 17: break; }} | switch(val){{ case 17: break; default: break; }} | Add default case. | Java |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
{{'name':'info'}} | {{"name":"info"}} | Use double quotes. | JSON |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
raise 'info' | raise Exception('info') | Raise needs an exception class. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
[x*x for x in data if x > 20] | [x*x for x in data if x > 20] | Correct list comprehension. | Python |
match b {{ 1 => {{}} }} | match b {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
var x int | var x int | Correct. | Go |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
print 'test' | print('test') | print needs parentheses. | Python |
100index = 10 | index100 = 10 | Variable cannot start with digit. | Python |
if (index = 40) {{}} | if (index === 40) {{}} | Use === for equality. | JavaScript |
if y = 78: | if y == 78: | Use == for comparison. | Python |
[x*x for x in arr if x > 77] | [x*x for x in arr if x > 77] | Correct list comprehension. | Python |
int values[66]; values[66]=5; | int values[66]; if(66<66){{}} else values[66]=5; | Bounds check. | C++ |
cin >> index; | int index;
cin >> index; | Declare variable. | C++ |
index == '69' | index === 69 | Use strict equality. | JavaScript |
function handle(num)
print(num)
end | function handle(num)
print(num)
end | Correct. | Lua |
for (x in items) | for (x of items) | for...in iterates keys. | JavaScript |
if result = 49 | if result == 49 | Use ==. | Go |
<p>output <b>data</p></b> | <p>output <b>data</b></p> | Nest properly. | HTML |
print('data') | print('data') | Correct. | R |
INSERT INTO products VALUES ('world',93) | INSERT INTO products (name, status) VALUES ('world',93); | Specify columns. | SQL |
if result = 9: | if result == 9: | Use == for comparison. | Python |
object Item {{ def main(args: Array[String]) = println("message") }} | object Item {{ def main(args: Array[String]): Unit = println("message") }} | Add return type Unit. | Scala |
JOIN profiles ON products.id = profiles.id | JOIN profiles ON products.id = profiles.id | Correct. | SQL |
class = 'hello' | class_name = 'hello' | 'class' is a keyword. | Python |
void main() {{ print('world') }} | void main() {{ print('world'); }} | Add semicolon. | Dart |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
values(62) | if length(values) >= 62, values(62), end | Check length. | MATLAB |
my @arr = (26,85,56); | my @arr = (26,85,56); | Correct. | Perl |
$x = 70; if ($x = 70) {{}} | $x = 70; if ($x == 70) {{}} | Use ==. | PHP |
val y = 94; y = 74 | var y = 94; y = 74 | Use var for reassignment. | Scala |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
class User {{ int temp; }}
obj.temp=5; | class User {{ public int temp; }}
obj.temp=5; | Make field public. | Java |
{{'name':13, 'age' 55}} | {{'name':13, 'age':55}} | Colon missing. | Python |
if b = 48 | if b == 48 | Use ==. | Ruby |
def process
puts 'test'
end | def process
puts 'test'
end | Correct. | Ruby |
if ($temp = 17) {{}} | if ($temp -eq 17) {{}} | Use -eq. | PowerShell |
x := 17 | x := 17 | Correct. | Go |
let a: Int = 'result' | let a: String = 'result' | Fix type. | Swift |
let foo = 19; let foo = 9; | let foo = 19; foo = 9; | Duplicate declaration. | JavaScript |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
while val > 64
val -= 1 | while val > 64:
val -= 1 | Colon missing after while. | Python |
#content {{ color: red; }} | #content {{ color: red; }} | Correct. | CSS |
name: hello
age: 96 | name: hello
age: 96 | Correct. | YAML |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
{ "name": "message" } | { "name": "message" } | Correct. | JSON |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
var foo int = 'world' | var foo string = 'world' | Type mismatch. | Go |
let count = 'message' | let count = "message" | Double quotes. | Swift |
String y = 'value'; | String y = "value"; | Double quotes. | Java |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
String name = 'test'; | String name = 'test'; | Correct. | Dart |
function baz() {{
return
{{key:'value'}}
}} | function baz() {{
return {{key:'value'}};
}} | Return object on same line. | JavaScript |
raise 'world' | raise Exception('world') | Raise needs an exception class. | Python |
random.sqrt(90) | import random
random.sqrt(90) | Import module first. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
if (bar = 27) | if (bar == 27) | Use ==. | R |
cin >> b
cout << b; | cin >> b;
cout << b; | Add semicolon. | C++ |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
int[] values = new int[99];
values[99] = 5; | int[] values = new int[99];
if (99 < values.length) values[99] = 5; | Check bounds. | Java |
def baz(index):
return index + 1 | def baz(index):
return index + 1 | Correct. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
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