Various programming languages decimal | time | Base64 and other operations of the quick look-up table

Switch between languages , At this time, a bad pen is better than a good memory . Sort out the processing of rounding decimals in various languages , String and time are exchanged ,base And so on ,

Round to two decimal places

# js
"12.125".toFixed(2)

#python
print(＂%.2f＂ % a)

# mysql
select round(a,2)

#golang
value = math.Trunc(value*1e2+0.500000001) * 1e-2
result, _ := strconv.ParseFloat(fmt.Sprintf("%.2f", value), 64)

#java
BigDecimal value =  value1.setScale(2,RoundingMode.HALF_UP)

String to time

# python
datetime.strptime(start_time, "%Y-%m-%d %H:%M")

# java
Date date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(str)

# golang
sd, _ := time.Parse("2006-01-02", start)

Time to string

# python
datetime.strftime()
datetime.now().strftime("%Y-%m-%d %X")

# java
String str = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(date);
//LocalDateTime form 
DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss").format(new LocalDateTime());

# golang
time.Now().Format("2006-01-02"),

File transfer base64

# dart(flutter)
var image = File(picPath);
var startDate = new DateTime.now();
List<int> imageBytes = await image.readAsBytes();
var fileBase64 =  'data:image/jpeg;base64,'+base64Encode(imageBytes);

base64 code

# java
Base64.getEncoder().encodeToString((str).getBytes())

base64 decode

# java
Base64.getDecoder().decode(data)

Get the current timestamp

# java
new Date().time();

# golang
timeUnixNano:=time.Now().UnixNano()

# dart
new DateTime.now().millisecondsSinceEpoch

# python
datetime.now().timestamp()

turn 13 A time stamp

# python Version is 2.7.~  The old version 
#  Current time conversion  
struct_time = datetime.now().timetuple()
print(int(round(time.mktime(struct_time)* 1000)))
# String conversion 
struct_time = time.strptime("2021-10-15 11:04:19", "%Y-%m-%d %H:%M:%S")
print(int(round(time.mktime(struct_time)* 1000)))

Continuous updating …