Small turtle Python 14th lesson after class

String formatting symbols meaning

symbol	illustrate
%c	Formatting characters and their ASCII codes [>>> '%c' %97 'a']
%s	format string
%d	format integer
%O	format unsigned octal number
%x	format unsigned hexadecimal number
%X	format unsigned hexadecimal number (uppercase)
%f	Format a fixed-point number, specifying the precision after the decimal point
%e	Format fixed-point numbers in scientific notation
%E	Same as %e, format fixed-point numbers in scientific notation
%g	Decide to use %f or %e according to the size of the value
%G	The function is the same as %g, depending on the size of the value to use %f or %E

Formatting operator helper

symbol	illustrate
m.n	m is the minimum total width displayed and n is the number of digits after the decimal point
-	for left alignment
+	Display a plus sign (+) in front of positive numbers
#	Display '0o' in front of octal numbers and '0x' or '0X' in front of hexadecimal numbers
0	The displayed number is filled with '0' in front of the space instead of the space

String escape character meaning

symbol	illustrate
\'	apostrophe
\"	Double quotes
\a	system beeps
\b	backspace character
\n	newline
\t	Horizontal Tab (TAB)
\v	vertical tab
\r	carriage return
\f	form feed
\O	characters represented by octal numbers
\x	character represented by hexadecimal number
\0	represents a null character
\\	backslash

0. What will the following line of code print?

"{{1}}".format( "do not print", "print")

'{1}'

1. In the following code, what parameters are a, b, c?

>>> "{a} love {b}.{c}".format(a="I", b="FishC", c="com")
'I love FishC.com'

keyword arguments

2. In the following code, what parameters are {0}, {1}, {2}?

>>> "{0} love {1}.{2}".format("I", "FishC", "com")
'I love FishC.com'

positional parameters

3. If you want to display Pi = 3.14, how should the string in front of format be filled in?

''.format('Pi = ', 3.1415)

'{0}{1:.2f}'

Move your hands:

0. Write a binary conversion program, the program is demonstrated as follows (hint, you can use bin() BIF for decimal conversion binary):

num = input("Please enter an integer (input Q to end the program):") 
while num != 'Q': 
    if num.isdigit(): 
        num = int(num) 
        print('Decimal -> Hexadecimal: %d -> %#x'%(num,num)) 
        print('decimal -> hex: %d -> %#o'%(num,num)) 
        print('decimal -> hex System: %d -> '%num,bin(num)) 
        num = input("Please input an integer (input Q to end the program): ") 
    else: 
        if num == 'Q': 
            break 
        else: 
            num = input( "The input is illegal, please enter an integer (input Q to end the program):") 
Note: If there is no num=input statement in if, it will prompt int and str type problems

Small turtle Python 14th lesson after class

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