Python format()用法及代码示例

# Python3 program to demonstarte 
# the str.format() method 
  
# using format option in a simple string 
print ("{}, A computer science portal for geeks."
                        .format("GeeksforGeeks")) 
  
# using format option for a 
# value stored in a variable 
str = "This article is written in {}"
print (str.format("Python")) 
  
# formatting a string using a numeric constant 
print ("Hello, I am {} years old !".format(18)) 

# Python program demonstrating Index error 
  
# Number of placeholders are four but 
# there are only three values passed 
  
# parameters in format function. 
my_string = "{}, is a {} {} science portal for {}"
  
print (my_string.format("GeeksforGeeks", "computer", "geeks"))

# Python program using multiple place  
# holders to demonstrate str.format() method  
  
# Multiple placeholders in format() function 
my_string = "{}, is a {} science portal for {}"
print (my_string.format("GeeksforGeeks", "computer", "geeks")) 
  
# different datatypes can be used in formatting 
print ("Hi ! My name is {} and I am {} years old"
                            .format("User", 19)) 
  
# The values passed as parameters 
# are replaced in order of their entry 
print ("This is {} {} {} {}"
       .format("one", "two", "three", "four"))

# To demonstrate the use of formatters 
# with positional key arguments. 
  
# Positional arguments 
# are placed in order 
print("{0} love {1}!!".format("GeeksforGeeks", 
                                    "Geeks")) 
  
# Reverse the index numbers with the 
# parameters of the placeholders 
print("{1} love {0}!!".format("GeeksforGeeks", 
                                    "Geeks")) 
  
  
print("Every {} should know the use of {} {} programming and {}"
    .format("programmer", "Open", "Source", "Operating Systems")) 
  
  
# Use the index numbers of the 
# values to change the order that 
# they appear in the string 
print("Every {3} should know the use of {2} {1} programming and {0}"
        .format("programmer", "Open", "Source", "Operating Systems")) 
  
  
# Keyword arguments are called 
# by their keyword name 
print("{gfg} is a {0} science portal for {1}"
.format("computer", "geeks", gfg ="GeeksforGeeks"))

# Demonstrate ValueError while 
# doing forced type-conversions 
  
# When explicitly converted floating point 
# values to decimal with base-10 by 'd'  
# type conversion we encounter Value-Error. 
print("The temperature today is {0:d} degrees outside !"
                                        .format(35.567)) 
  
# Instead write this to avoid value-errors 
''' print("The temperature today is {0:.0f} degrees outside !" 
                                            .format(35.567))'''

# Convert base-10 decimal integers  
# to floating point numeric constants 
print ("This site is {0:f}% securely {1}!!". 
                    format(100, "encrypted")) 
  
# To limit the precision 
print ("My average of this {0} was {1:.2f}%"
            .format("semester", 78.234876)) 
  
# For no decimal places 
print ("My average of this {0} was {1:.0f}%"
            .format("semester", 78.234876)) 
  
# Convert an integer to its binary or 
# with other different converted bases. 
print("The {0} of 100 is {1:b}"
        .format("binary", 100)) 
          
print("The {0} of 100 is {1:o}"
        .format("octal", 100))

# To demonstrate spacing when  
# strings are passed as parameters 
print("{0:4}, is the computer science portal for {1:8}!"
                        .format("GeeksforGeeks", "geeks")) 
  
# To demonstrate spacing when numeric 
# constants are passed as parameters. 
print("It is {0:5} degrees outside !"
                        .format(40)) 
  
# To demonstrate both string and numeric 
# constants passed as parameters 
print("{0:4} was founded in {1:16}!"
    .format("GeeksforGeeks", 2009)) 
  
  
# To demonstrate aligning of spaces 
print("{0:^16} was founded in {1:<4}!"
        .format("GeeksforGeeks", 2009)) 
  
print("{:*^20s}".format("Geeks"))

# which prints out i, i ^ 2, i ^ 3, 
#  i ^ 4 in the given range 
  
# Function prints out values 
# in an unorganized manner 
def unorganized(a, b):
    for i in range (a, b):
        print ( i, i**2, i**3, i**4 ) 
  
# Function prints the organized set of values 
def organized(a, b):
    for i in range (a, b):
  
        # Using formatters to give 6  
        # spaces to each set of values 
        print("{:6d} {:6d} {:6d} {:6d}"
        .format(i, i ** 2, i ** 3, i ** 4)) 
  
# Driver Code 
n1 = int(input("Enter lower range:-\n")) 
n2 = int(input("Enter upper range:-\n")) 
  
print("------Before Using Formatters-------") 
  
# Calling function without formatters 
unorganized(n1, n2) 
  
print() 
print("-------After Using Formatters---------") 
print() 
  
# Calling function that contain 
# formatters to organize the data 
organized(n1, n2)