Python string format output: print()

Python Function USES :print()

• effect ： Print string or numeric value

• grammar ：print( Variable 1[, Variable 2[, Variable 3[,...]]], seq= Specify the separator , end= Terminator )

There are two common ways :

1. print(" Formatted string "%( parameter list ))

   for example :

name = " Zhang San "
age = 14
print("%s Age is %d"%(name, age))

2. Use format() Format in

   for example :

name = " Zhang San "
age = 14
print("{} Age is {}".format(name, age))

{} Can be called " Slot ", It is equivalent to a placeholder .format Method will fill the slot of the format string with parameters . If you do not specify the number of parameters to fill the slot , The default is to match from left to right format Variables in the parameter list .

• “ Slot ” Specify the case of filling parameters :

name = " Zhang San "
age = 14
print("{0} Age is {1}".format(name, age))
print("{1} Age is {0}".format(name, age))

 The result is :
Zhang San's age is 14
14 Age is Zhangsan

format Method , The number of the first parameter is 0, The following parameter numbers are incremented by one .

3. format() Further use of method formatting

Grammar format :{< Parameter number >:< Format control flag >}

Example :print("{0:=^20} Age is {1:*>10}".format(name, age))

result :========= Zhang San ========= Age is ********14

explain : There are six types of format control tags , Divide the six into two groups to remember ： The first group : fill , alignment , Width ; The second group ：<,>,<. precision >,< type >.

• fill : A character used to fill in white space . such as , Specify the character as "=“, The output width is controlled to 5, Output string "123”, The alignment is right , So the output is :==123. If you do not specify this character , Then the blank character is filled by default .

• alignment : Specify the alignment of the output object .^ Align center ,< Align left ,> Right alignment .

• Width ： Specifies the width occupied by the output object . If the required width of the output object itself is less than the specified width , Then according to its alignment , Fill the blank character with the specified fill character .

• <,>: Render the output number as its thousandth separator .print("{:,}".format(100000000))

  result :100,000,000

• <. precision >: Specify the precision of the output value , Or string length

Example :print("{:.2f}".format(20.123456))

result :20.12

• < type >: Specify the output type

Example :print("{0:d}\t{0:.2f}".format(1000))

result :1000 1000.00

When specifying a format control tag in a slot , Follow as much as possible fill , alignment , Width ,<,>,<. precision >,< type > The order of . Otherwise, an error will be reported .

Reference material :

Python format Format function | Novice tutorial (runoob.com)

Python Language programming (MOOC) Song Tian