About format formatting output and format formatting

About format formatting output and format formatting

What isFormat?

Compared with the basic formatting output, the "%" method is used. The format function is powerful. This function uses the string as a template and uses the input parameters for formatting, the braces "{}" are used as special characters instead of "%", which is similar to the placeholder in C #.

1)FormatBasic usage

No ID, that is, "{}"

With a number, you can change the order, that is, "{1}", "{2 }"

With the keyword "{a}", "{tom }"

 

For example:

Name = "Sandy"

Gender = "female"

Age = 18

Print ("name: % s, gender: % s age: % d" % (name, gender, age ))

Print ("name :{}, gender :{} age :{}". format (name, gender, age ))

# You can call it multiple times with a number.

Print ("name: {0}, gender: {1} age: {2} Student name: {0}". format (name, gender, age ))

# Easy to understand the ID name

Print ("name: {name}, gender: {gender} age: {age} Student name: {name }". format (name = name, gender = gender, age = age ))

 

Demo:

 

 

2) Advanced usage of format

<(Default) left alignment,> right alignment, ^ center alignment

Number of digits: "{: 4 s}", "{:. 2f}", etc.

 

For example:

Print ("name: {: 10}". format (name) # left aligned by default

Print ("name: {: <10}". format (name) # Left-aligned logo

Print ("name: {:> 10}". format (name) # right alignment

Print ("name: {: ^ 10}". format (name) # center alignment

Print ("{:. 2f}". format (3.1415926) # retain two valid digits

Print ("{: 10.2f}". format (3.1415926) # retain two valid digits, which are right aligned by default.

Print ("{:> 10.2f}". format (3.1415926) # retain two valid digits to indicate the right alignment

Print ("{: <10.2f}". format (3.1415926) # retain two valid digits to indicate the left alignment

Print ("{: ^ 10.2f}". format (3.1415926) # Keep two valid digits in the middle of the alignment.

Demo:

 

3)FormatValue

• "B" binary. The number is output in the base of two digits.
• "C" character, convert the integer to the corresponding unicode string before printing
• "D" decimal number. The number is output based on 10.
• "O" Octal numbers, which are output based on 8
• "X" hexadecimal number. The number is output based on 16. a-f is used to represent more than 9 digits.
• "E" power symbol, which is used to print numbers in scientific notation. Use "e" to represent the power
• "G" is in the general format. Numbers are output in fixed-point format. When the value is very large, the numbers are printed in the power form.
• "N" number. If the value is an integer, it is the same as "d". If the value is a floating point, it is the same as "g". The difference is that it inserts a digital separator according to the region settings.
• "%" Percent, numeric value multiplied by 100 print, retain 6 decimal places, the value will be followed by a percent sign
• "," Thousands separator, often used for currency representation or big data values

 

For example:

Num01, num02 = 200,300

Print ("hexadecimal print: {0: x} {1: x}". format (num01, num02 ))

Print (": {0: o} {1: o}". format (num01, num02 ))

Print ("binary print: {0: B} {1: B}". format (num01, num02 ))

Print ("{0: c}". format (76) # encode a specific character. For more information, see ASCll

Print ("{: e}". format (123456.77544) # retain 6 digits after the decimal point by default

Print ("{: 0.2e}". format (123456.77544) # retain two digits after the decimal point

Print ("{: g}". format (123456.77544) # retain 6 digits

Print ("{: g}". format (123456789.77544) # more than 6 digits are represented by scientific notation

Print ("{: %}". format (34) # retain 6 digits after the decimal point by default

Print ("{: 0.2%}". format (34 ))

Print ("{:,}". format (1234567890 ))

 

Demo: