wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
data[97] | if (length(data) >= 97) data[97] | Check length. | R |
WHERE name = '49' | WHERE name = 49 | Don't quote integer. | SQL |
if bar > 45
print('hello') | if bar > 45:
print('hello') | Colon missing after if. | Python |
data[43] | if data.indices.contains(43) {{ data[43] }} | Check index. | Swift |
if (index) console.log('yes') else console.log('no') | if (index) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
object Order {{ def main(args: Array[String]) = println("result") }} | object Order {{ def main(args: Array[String]): Unit = println("result") }} | Add return type Unit. | Scala |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
if (result = 100) | if (result == 100) | Use ==. | C++ |
if (z = 85) {} | if (z == 85) {} | Use ==. | Dart |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
{{'name':'test'}} | {{"name":"test"}} | Use double quotes. | JSON |
if ($temp = 69) {{}} | if ($temp -eq 69) {{}} | Use -eq. | PowerShell |
52result = 10 | result52 = 10 | Variable cannot start with digit. | Python |
cin >> c; | int c;
cin >> c; | Declare variable. | C++ |
for (int i=0; i<58; i++) {{}} | for (int i=0; i<58; i++) {{}} | Correct. | Java |
'result' + 33 | 'result' + 33.to_s | Convert int. | Ruby |
let c = 30; c += 1; | let mut c = 30; c += 1; | Need mut to modify. | Rust |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
bar == '60' | bar === 60 | Use strict equality. | JavaScript |
jwt.sign({{id:27}}, 'key'); | jwt.sign({{id:27}}, 'key', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
with open('config.json') as file_handle:
data = file_handle.read() | with open('config.json') as file_handle:
data = file_handle.read() | Correct. | Python |
my @arr = (78,43,15); | my @arr = (78,43,15); | Correct. | Perl |
println('output') | println("output") | Double quotes. | Scala |
fmt.Println 'data' | fmt.Println('data') | Missing parentheses. | Go |
List(28,28,30) | List(28,28,30) | Correct. | Scala |
Write-Host 'info' | Write-Host 'info' | Correct. | PowerShell |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
SELECT id status FROM items; | SELECT id, status FROM items; | Add comma. | SQL |
if ($count = 50) | if ($count == 50) | Use ==. | Perl |
const y = 71; y = 88; | let y = 71; y = 88; | Cannot reassign const. | JavaScript |
if [ $item = 48 ]; then | if [ "$item" = 48 ]; then | Quote variable. | Shell |
<input type='text' value='hello'> | <input type='text' value='hello' name='title'> | Add name attribute. | HTML |
list.forEach(function(b) {{ console.log(b); }}) | list.forEach((b) => {{ console.log(b); }}) | Arrow functions are cleaner. | JavaScript |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
while val > 77
val -= 1 | while val > 77:
val -= 1 | Colon missing after while. | Python |
x := 81 | x := 81 | Correct. | Go |
// comment | /* comment */ | Use /* */. | CSS |
{{"title":"output" "status":80}} | {{"title":"output", "status":80}} | Add comma. | JSON |
if (foo = 28) {{}} | if (foo === 28) {{}} | Use === for equality. | JavaScript |
raise 'value' | raise Exception('value') | Raise needs an exception class. | Python |
cin >> result
cout << result; | cin >> result;
cout << result; | Add semicolon. | C++ |
[35, 78, 75 | [35, 78, 75] | Close bracket. | Ruby |
<table><tr><td>hello<td>test</tr></table> | <table><tr><td>hello</td><td>test</td></tr></table> | Close td. | HTML |
SELECT * FROM orders WHRE email=42; | SELECT * FROM orders WHERE email=42; | Fix WHERE. | SQL |
let vec=vec![46,37,86]; let primary=&vec[0]; vec.push(93); | let mut vec=vec![46,37,86]; let primary=vec[0]; vec.push(93); | Copy instead of reference. | Rust |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
<user name='value'/> | <user name="value"/> | Double quotes. | XML |
if z = 82: | if z == 82: | Use == for comparison. | Python |
switch(count){{ case 14: break; }} | switch(count){{ case 14: break; default: break; }} | Add default case. | Java |
String y = 'message'; | String y = "message"; | Double quotes. | Java |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
<hr></hr> | <hr> | Self-closing. | HTML |
match y {{ 1 => {{}} }} | match y {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
val count = 'hello' | val count = "hello" | Double quotes. | Kotlin |
h1 {{ font-size:26px color:#333; }} | h1 {{ font-size:26px; color:#333; }} | Add semicolon. | CSS |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
class Product {{ int x; }}
obj.x=5; | class Product {{ public int x; }}
obj.x=5; | Make field public. | Java |
else
print('test') | else:
print('test') | Colon after else. | Python |
for (count in arr) | for (count of arr) | for...in iterates keys. | JavaScript |
yield val | yield val | Correct yield. | Python |
void main() {{ print('world') }} | void main() {{ print('world'); }} | Add semicolon. | Dart |
echo message data | echo 'message data' | Quote to prevent splitting. | Shell |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(52); | const http = require('http'); http.createServer((req,res) => res.end('result')).listen(52); | Correct. | Node.js |
for temp in range(99)
print(temp) | for temp in range(99):
print(temp) | Colon after for. | Python |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
String name = 'test'; | String name = 'test'; | Correct. | Dart |
console.log('value' | console.log('value') | Close parenthesis. | JavaScript |
val count: Int = 'result' | val count: String = 'result' | Fix type. | Kotlin |
{{'id':70, 'name' 11}} | {{'id':70, 'name':11}} | Colon missing. | Python |
UPDATE users SET email='world' WHERE status=31 | UPDATE users SET email='world' WHERE status=31; | Add semicolon. | SQL |
if result = 90 | if result == 90 | Use ==. | Go |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
val y = 32; y = 49 | var y = 32; y = 49 | Use var for reassignment. | Scala |
let a: i32 = "data"; | let a: &str = "data"; | Type mismatch. | Rust |
let num = 83; let num = 67; | let num = 83; num = 67; | Duplicate declaration. | JavaScript |
if val = 97 {{}} | if val == 97 {{}} | Use ==. | Swift |
function process(x:string){{return x;}} process(78); | function process(x:string){{return x;}} process('output'); | Pass correct type. | TypeScript |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
def process():
print('info') | def process():
print('info') | Indent function body. | Python |
list[52] | if (list.indices.contains(52)) list[52] | Check index. | Kotlin |
let s1 = String::from("message"); let s2 = s1; println!("{{}}", s1); | let s1 = String::from("message"); let s2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
compute | compute() | Add parentheses. | Kotlin |
'hello' + 83 | 'hello' + str(83) | Can't add int to string. | Python |
const foo; | const foo = 60; | Initialize const. | JavaScript |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
if (b = 48) {{}} | if (b == 48) {{}} | Use ==. | Kotlin |
foo | foo() | Add parentheses. | Swift |
if x = 71 | if x == 71 | Use ==. | MATLAB |
{{"title":"value",}} | {{"title":"value"}} | Remove trailing comma. | JSON |
index = value | index = 'value' | Quote strings. | Python |
<person><name>message</name><desc>13</desc></person | <person><name>message</name><desc>13</desc></person> | Add closing >. | XML |
int[] items = new int[59];
items[59] = 5; | int[] items = new int[59];
if (59 < items.length) items[59] = 5; | Check bounds. | Java |
let text = String::from("test"); let ref=&text; text.push_str("!"); | let mut text = String::from("test"); let ref=&text; println!("{{}}", ref); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
if (count = 69) {{}} | if (count == 69) {{}} | Use ==. | Java |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
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