a= 1
b = 2


a = a + b
b = a - b
a = a - b
print ('a = {0}, b = {1}'.format(a,b))

print ("a={1} b={0} {1}".format("hello", "world")) 

a = a ^ b
b = a ^ b
a = a ^ b
print 'a=%d' %a +',b=%d' %b

print 'Price of eggs: $%d' % 42

輸出

a = 2, b = 1
a=world b=hello world
a=1,b=2
Price of eggs: $42

上述植入了兩種交換a和b值的例子，^是按位異或。

if i % 30 == 0:
    print("image:", '%04d' % (i+1),\
    "cost=", "{:.9f}".format(loss))

('image:', '0001', 'cost=', '3.899574518')
('image:', '0031', 'cost=', '2.469503164')
('image:', '0061', 'cost=', '1.211874366')
('image:', '0091', 'cost=', '0.633342564')
('image:', '0121', 'cost=', '0.465918243')

以上只是程式碼段。.9f 的意思是：dot後面是精度，如

>>>from math import pi

>>>"Pi with three decimals: %.3f"% pi

Pi with three decimals: 3.142

dot前是指定位寬，指的是整個數的位寬（包括小數位），這樣做的目的之一是前面補0。

>>>'%04d'% pi
'0003'