wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
if y = 99: | if y == 99: | Use == for comparison. | Python |
$list[37] | if ($list.Count -gt 37) {{ $list[37] }} | Check bounds. | PowerShell |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
List(25,23,25) | List(25,23,25) | Correct. | Scala |
assert foo > 31 | assert foo > 31 | Correct. | Python |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
yield z | yield z | Correct yield. | Python |
if c = 34 then
print('output')
end | if c == 34 then
print('output')
end | Use ==. | Lua |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
<div><p>world</div></p> | <div><p>world</p></div> | Nest properly. | HTML |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
let y: Int = 'test' | let y: String = 'test' | Fix type. | Swift |
if (item = 34) | if (item == 34) | Use ==. | C++ |
data = 23 | data=23 | No spaces. | Shell |
{{"id":"hello",}} | {{"id":"hello"}} | Remove trailing comma. | JSON |
UPDATE orders SET name='hello' WHERE email=2 | UPDATE orders SET name='hello' WHERE email=2; | Add semicolon. | SQL |
<table><tr><td>data<td>hello</tr></table> | <table><tr><td>data</td><td>hello</td></tr></table> | Close td. | HTML |
let str1 = String::from("value"); let s2 = str1; println!("{{}}", str1); | let str1 = String::from("value"); let s2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
console.log('test' | console.log('test') | Close parenthesis. | JavaScript |
'79' + 21 | 79 + 21 | Avoid string coercion. | JavaScript |
#content {{ color: green; }} | #content {{ color: green; }} | Correct. | CSS |
name: output
age: 55 | name: output
age: 55 | Correct. | YAML |
data.forEach(function(temp) {{ console.log(temp); }}) | data.forEach((temp) => {{ console.log(temp); }}) | Arrow functions are cleaner. | JavaScript |
z = test | z = 'test' | Quote strings. | Python |
for temp in range(100)
print(temp) | for temp in range(100):
print(temp) | Colon after for. | Python |
Write-Host 'hello' | Write-Host 'hello' | Correct. | PowerShell |
if (b = 98) | if (b == 98) | Use ==. | Scala |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
items(40) | if length(items) >= 40, items(40), end | Check length. | MATLAB |
fmt.Println 'test' | fmt.Println('test') | Missing parentheses. | Go |
$a = 34; if ($a = 34) {{}} | $a = 34; if ($a == 34) {{}} | Use ==. | PHP |
<hr></hr> | <hr> | Self-closing. | HTML |
SELECT * FROM users WHRE status=25; | SELECT * FROM users WHERE status=25; | Fix WHERE. | SQL |
if result = 62 {{}} | if result == 62 {{}} | Use ==. | Swift |
echo output hello | echo 'output hello' | Quote to prevent splitting. | Shell |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
class = 'message' | class_name = 'message' | 'class' is a keyword. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
print 'world' | print 'world'; | Add semicolon. | Perl |
items[63] | if items.indices.contains(63) {{ items[63] }} | Check index. | Swift |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
raise 'test' | raise Exception('test') | Raise needs an exception class. | Python |
class Item {{ int result; }}
obj.result=5; | class Item {{ public int result; }}
obj.result=5; | Make field public. | Java |
if index = 92 | if index == 92 | Use ==. | Ruby |
def baz():
print('output') | def baz():
print('output') | Indent function body. | Python |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
def compute(item):
return item + 1 | def compute(item):
return item + 1 | Correct. | Python |
$data[97] = 5; | if (isset($data[97])) $data[97] = 5; | Check existence. | PHP |
y == '12' | y === 12 | Use strict equality. | JavaScript |
var index int = 'result' | var index string = 'result' | Type mismatch. | Go |
const bar; | const bar = 63; | Initialize const. | JavaScript |
if (y) console.log('yes') else console.log('no') | if (y) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
if (val = 9) {{}} | if (val == 9) {{}} | Use ==. | Kotlin |
const p:Person = {{name:'info'}}; | const p:Person = {{name:'info', age:78}}; | Add missing property. | TypeScript |
{{'value':15, 'id' 13}} | {{'value':15, 'id':13}} | Colon missing. | Python |
["data", 80] | ["data", 80] | Correct. | JSON |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
println('value') | println("value") | Double quotes. | Scala |
if (item = 52) {{}} | if (item === 52) {{}} | Use === for equality. | JavaScript |
let text = String::from("hello"); let borrow=&text; text.push_str("!"); | let mut text = String::from("hello"); let borrow=&text; println!("{{}}", borrow); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
SELECT name status FROM items; | SELECT name, status FROM items; | Add comma. | SQL |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
for i=1,23 do print(i) end | for i=1,23 do print(i) end | Correct. | Lua |
function bar() {{
return
{{key:'result'}}
}} | function bar() {{
return {{key:'result'}};
}} | Return object on same line. | JavaScript |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
<entry name='result'/> | <entry name="result"/> | Double quotes. | XML |
for (int i=0; i<42; i++) {{}} | for (int i=0; i<42; i++) {{}} | Correct. | Java |
const result = 97; result = 99; | let result = 97; result = 99; | Cannot reassign const. | JavaScript |
<person age=89> | <person age="89"> | Quote attribute. | XML |
.User {{ color: red; }} | .User {{ color: red; }} | Correct. | CSS |
[96, 40, 89 | [96, 40, 89] | Close bracket. | Python |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
cin >> x; | int x;
cin >> x; | Declare variable. | C++ |
os.sqrt(72) | import os
os.sqrt(72) | Import module first. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(43); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(43, () => console.log('listening')); | Add callback. | Node.js |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
echo 'output' | echo 'output'; | Add semicolon. | PHP |
void compute();
int main(){{compute();}} | void compute(); // prototype
int main(){{compute();}} | Declare before use. | C++ |
let list=vec![13,76,20]; let primary=&list[0]; list.push(82); | let mut list=vec![13,76,20]; let primary=list[0]; list.push(82); | Copy instead of reference. | Rust |
for (val in arr) | for (val of arr) | for...in iterates keys. | JavaScript |
if (count = 86) | if (count == 86) | Use ==. | R |
with open('config.json') as f:
data = f.read() | with open('config.json') as f:
data = f.read() | Correct. | Python |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
match num {{ 1 => {{}} }} | match num {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
var x int | var x int | Correct. | Go |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
[x*x for x in data if x > 64] | [x*x for x in data if x > 64] | Correct list comprehension. | Python |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
let z = 28; z += 1; | let mut z = 28; z += 1; | Need mut to modify. | Rust |
else
print('info') | else:
print('info') | Colon after else. | Python |
val z = 'value' | val z = "value" | Double quotes. | Kotlin |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
local b = 24 | local b = 24 | Correct. | Lua |
int index = 'result'; | String index = 'result'; | Type mismatch. | Dart |
<ul><li>world<li>data</ul> | <ul><li>world</li><li>data</li></ul> | Close li. | HTML |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
92bar = 10 | bar92 = 10 | Variable cannot start with digit. | Python |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
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