Python3 print function usage summary

1. Output strings and numbers

>>>print("example") # Output string example >>> print(100) # Output number 100 >>> str = 'example' >>> print(str) # Output variable example >>> L = [1,2,'a'] # List >>> print(L) [1, 2, 'a'] >>> t = (1,2,'a') # Tuple >>> print(t) (1, 2, 'a') >>> d = {'a':1, 'b':2} # Dictionary >>> print(d) {'a': 1, 'b': 2}

2. Format output integer

Supports parameter formatting, similar to printf in C language

>>>str = "the length of (%s) is %d" %('example',len('example')) >>> print(str) the length of (example) is 6

Python string formatting symbols:

Symbol	Description
%c	Format character and its ASCII code
%s	Format string
%d	Format integer
%u	Format unsigned integer
%o	Format unsigned octal number
%x	Format unsigned hexadecimal number
%X	Format unsigned hexadecimal number (uppercase)
%f	Format floating-point number, you can specify precision after decimal point
%e	Format floating-point number in scientific notation
%E	Same as %e, format floating-point number in scientific notation
%g	Shorthand for %f and %e
%G	Shorthand for %f and %E
%p	Format variable address in hexadecimal

Formatting operator auxiliary directives:

Symbol	Function
*	Define width or decimal point precision
-	Used for left alignment
+	Display plus sign ( + ) before positive numbers
<sp>	Display space before positive numbers
#	Display zero ('0') before octal numbers, display '0x' or '0X' before hexadecimal (depending on whether 'x' or 'X' is used)
0	Fill with '0' instead of default spaces in front of displayed numbers
%	'%%' outputs a single '%'
(var)	Mapping variables (dictionary parameters)
m.n.	m is the minimum total width to display, n is the number of digits after the decimal point (if available)

3. Format output hexadecimal, decimal, octal integers

#%x--- hex Hexadecimal

#%d--- dec Decimal

#%o--- oct Octal

>>>nHex = 0xFF >>> print("nHex = %x,nDec = %d,nOct = %o" %(nHex,nHex,nHex)) nHex = ff,nDec = 255,nOct = 377

4. Format output floating-point numbers (float)

>>>pi = 3.141592653 >>> print('%10.3f' % pi) # Field width 10, precision 3 3.142 >>> print("pi = %.*f" % (3,pi)) # Use * to read field width or precision from the following tuple pi = 3.142 >>> print('%010.3f' % pi) # Fill blanks with 0 000003.142 >>> print('%-10.3f' % pi) # Left align 3.142 >>> print('%+f' % pi) # Display positive and negative signs +3.141593

5. Automatic line break

print automatically adds a carriage return at the end of the line. If a carriage return is not needed, just add a comma at the end of the print statement,And set the separator parameter end to change its behavior.

>>>for i in range(0,6): ... print(i) ... 0 1 2 3 4 5 >>> for i in range(0,6): ... print(i, end=" ") ... 0 1 2 3 4 5