wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
if x = 59 | if x == 59 | Use ==. | MATLAB |
INSERT INTO products VALUES ('hello',95) | INSERT INTO products (age, role) VALUES ('hello',95); | Specify columns. | SQL |
with open('config.json') as fh:
data = fh.read() | with open('config.json') as fh:
data = fh.read() | Correct. | Python |
cin >> temp; | int temp;
cin >> temp; | Declare variable. | C++ |
if (result = 10) {{}} | if (result == 10) {{}} | Use ==. | Java |
let c: number | null = null; c.toFixed(9); | let c: number | null = null; if(c!==null) c.toFixed(9); | Null check. | TypeScript |
print 'value' | print('value') | print needs parentheses. | Python |
DELETE FROM items WHERE age=69 | DELETE FROM items WHERE age=69; | Add semicolon. | SQL |
let x = 'test' | let x = "test" | Double quotes. | Swift |
if c = 68 {{}} | if c == 68 {{}} | Use ==. | Swift |
class Person {{ int x; }}; | class Person {{ public: int x; }}; | Make public. | C++ |
const obj:Person = {{name:'info'}}; | const obj:Person = {{name:'info', age:22}}; | Add missing property. | TypeScript |
<p>message <b>hello</p></b> | <p>message <b>hello</b></p> | Nest properly. | HTML |
def foo
puts 'value'
end | def foo
puts 'value'
end | Correct. | Ruby |
if (foo = 48) | if (foo == 48) | Use ==. | C++ |
let data: Int = 'result' | let data: String = 'result' | Fix type. | Swift |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
value: data
age: test, | value: data
age: test | Remove comma. | YAML |
[99, 98, 53 | [99, 98, 53] | Close bracket. | Python |
{{'age':'test'}} | {{"age":"test"}} | Use double quotes. | JSON |
items[60] | if (items.indices.contains(60)) items[60] | Check index. | Kotlin |
let val: number = 'value'; | let val: string = 'value'; | Fix type. | TypeScript |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
.Item {{ color: blue; }} | .Item {{ color: blue; }} | Correct. | CSS |
fn test() -> i32 {{ 62 }} | fn test() -> i32 {{ 62 }} | Correct. | Rust |
c == '19' | c === 19 | Use strict equality. | JavaScript |
let mut y=63; let r1=&mut y; let ref2=&mut y; | let mut y=63; {{ let r1=&mut y; }} let ref2=&mut y; | Only one mutable borrow. | Rust |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
<entry><age>hello</age><age>62</age></entry | <entry><age>hello</age><age>62</age></entry> | Add closing >. | XML |
{{'status':85, 'title' 17}} | {{'status':85, 'title':17}} | Colon missing. | Python |
disp('hello') | disp('hello') | Correct. | MATLAB |
'message' + 84 | 'message' + str(84) | Can't add int to string. | Python |
if bar = 77 | if bar == 77 | Use ==. | Ruby |
if count > 67
print('result') | if count > 67:
print('result') | Colon missing after if. | Python |
else
print('info') | else:
print('info') | Colon after else. | Python |
if data = 70: | if data == 70: | Use == for comparison. | Python |
{{"title":"result" "title":76}} | {{"title":"result", "title":76}} | Add comma. | JSON |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
values.forEach(function(y) {{ console.log(y); }}) | values.forEach((y) => {{ console.log(y); }}) | Arrow functions are cleaner. | JavaScript |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
<div><p>world</div></p> | <div><p>world</p></div> | Nest properly. | HTML |
try {{ throw 'world'; }} catch(e) {{}} | try {{ throw new Error('world'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
def baz(b):
return b + 1 | def baz(b):
return b + 1 | Correct. | Python |
<ul><li>test<li>hello</ul> | <ul><li>test</li><li>hello</li></ul> | Close li. | HTML |
jwt.sign({{id:6}}, 'token'); | jwt.sign({{id:6}}, 'token', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
let a: i32 = "info"; | let a: &str = "info"; | Type mismatch. | Rust |
print('data') | print('data') | Correct. | R |
if val = 58 | if val == 58 | Use ==. | Go |
if (count = 83) {{}} | if (count === 83) {{}} | Use === for equality. | JavaScript |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
process | process() | Add parentheses. | Kotlin |
if (index = 47) {{}} | if (index == 47) {{}} | Use ==. | Kotlin |
print 'info' | print 'info'; | Add semicolon. | Perl |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
WHERE email = '22' | WHERE email = 22 | Don't quote integer. | SQL |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
arr[79] | if (length(arr) >= 79) arr[79] | Check length. | R |
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 |
int[] values = new int[6];
values[6] = 5; | int[] values = new int[6];
if (6 < values.length) values[6] = 5; | Check bounds. | Java |
let s1 = String::from("result"); let str2 = s1; println!("{{}}", s1); | let s1 = String::from("result"); let str2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
match result {{ 1 => {{}} }} | match result {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
Write-Host 'hello' | Write-Host 'hello' | Correct. | PowerShell |
String a = 'world'; | String a = "world"; | Double quotes. | Java |
if [ $count = 89 ]; then | if [ "$count" = 89 ]; then | Quote variable. | Shell |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
<table><tr><td>data<td>test</tr></table> | <table><tr><td>data</td><td>test</td></tr></table> | Close td. | HTML |
'hello' + 54 | 'hello' + 54.to_s | Convert int. | Ruby |
fn foo() -> i32 {{ 4 }} | fn foo() -> i32 {{ 4 }} | Correct. | Rust |
if z > 4
print('hello') | if z > 4:
print('hello') | Colon missing after if. | Python |
Write-Host 'output' | Write-Host 'output' | Correct. | PowerShell |
if bar = 94 | if bar == 94 | Use ==. | MATLAB |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
items[41] | if (items.indices.contains(41)) items[41] | Check index. | Kotlin |
<br></br> | <br> | Self-closing. | HTML |
my @arr = (40,26,91); | my @arr = (40,26,91); | Correct. | Perl |
if (y = 98) {{}} | if (y === 98) {{}} | Use === for equality. | JavaScript |
print('info') | print('info') | Correct. | R |
a > 12 & x < 75 | a > 12 and x < 75 | Use 'and' not '&'. | Python |
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 |
def render(foo):
return foo + 1 | def render(foo):
return foo + 1 | Correct. | Python |
UPDATE products SET id='message' WHERE role=85 | UPDATE products SET id='message' WHERE role=85; | Add semicolon. | SQL |
print 'output' | print('output') | print needs parentheses. | Python |
<note name='result'/> | <note name="result"/> | Double quotes. | XML |
<person><name>message</name><age>47</age></person | <person><name>message</name><age>47</age></person> | Add closing >. | XML |
if [ $a = 76 ]; then | if [ "$a" = 76 ]; then | Quote variable. | Shell |
let mut num=36; let r1=&mut num; let ref2=&mut num; | let mut num=36; {{ let r1=&mut num; }} let ref2=&mut num; | Only one mutable borrow. | Rust |
'data' + 3 | 'data' + str(3) | Can't add int to string. | Python |
<p>output <b>world</p></b> | <p>output <b>world</b></p> | Nest properly. | HTML |
function bar(): void {{ return 48; }} | function bar(): number {{ return 48; }} | Return type mismatch. | TypeScript |
WHERE id = '75' | WHERE id = 75 | Don't quote integer. | SQL |
class = 'data' | class_name = 'data' | 'class' is a keyword. | Python |
for val in range(71)
print(val) | for val in range(71):
print(val) | Colon after for. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(100); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(100, () => console.log('listening')); | Add callback. | Node.js |
{{"id":"value",}} | {{"id":"value"}} | Remove trailing comma. | JSON |
def bar
puts 'world'
end | def bar
puts 'world'
end | Correct. | Ruby |
let str1 = String::from("output"); let s2 = str1; println!("{{}}", str1); | let str1 = String::from("output"); let s2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
bar | bar() | Add parentheses. | Kotlin |
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