Learning with python: Chapter5~8 Fruitful functions, Iterations, Strings, Lists

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　　Examples:
　　

#  Fruitful functions
print "===========Fruitful functions============"
import math
def area(radius):
return math.pi*(radius**2)
mianji=area(2);
print mianji
def fibonacci(n):
if not isinstance(n,int):  # check parameters
print "Factorial is only for integer."
return -1;
elif n < 0:
print "Factorial is only for n>=0."
return -1;
elif n==0 or n==1:
return 1
else:
return fibonacci(n-1)+fibonacci(n-2)
fib = fibonacci(10);
print fib
fib = fibonacci(1.5);
print fib
fib = fibonacci(-10);
print fib

# test while
print "=========test while========="
def countdown(n):
while n > 0:
print n
n = n - 1
print "Blastoff!"
countdown(4)
x=1.0
while x < 10.0:
print x, '\t', math.log(x)
x = x + 1.0
def printMultiples(n):
i=1
whilei<=6:
print n*i,'\t',
i = i + 1
print
i=1
while i<=6:
printMultiples(i)
i = i + 1
# Strings
print "=======Strings======"
fruit="banana"
# i=0
# print isinstance(len(fruit),int);
# while i < len(fruit):
#print fruit
#i = i + 1
for char in fruit:
print char
prefixes = "JKLMNOPQ"
suffix = "ack"
for letter in prefixes:
print letter + suffix
s = "Peter, Paul, and Mary"
print s[0:5]
print s[7:11]
print s[17:21]
import string
index = string.find(fruit, "a")
print index
index = string.find(fruit, "na")
print index
print string.lowercase
print string.uppercase
print string.digits
# Lists
num = range(0,1,10);
str = ["xiahou", "zuoxin"];
print num, str
print "'xiahou' int str:", 'xiahou' in str  # membership
print "'xiah' int str:", 'xiah' not in str  # membership


　　Results:

===========Fruitful functions============
12.5663706144
89
Factorial is only for integer.
-1
Factorial is only for n>=0.
-1
=========test while=========
4
3
2
1
Blastoff!
1.0 0.0
2.0 0.69314718056
3.0 1.09861228867
4.0 1.38629436112
5.0 1.60943791243
6.0 1.79175946923
7.0 1.94591014906
8.0 2.07944154168
9.0 2.19722457734
1 2 3 4 5 6
2 4 6 8 10 12
3 6 9 12 15 18
4 8 12 16 20 24
5 10 15 20 25 30
6 12 18 24 30 36
=======Strings======
b
a
n
a
n
a
Jack
Kack
Lack
Mack
Nack
Oack
Pack
Qack
Peter
Paul
Mary
1
2
abcdefghijklmnopqrstuvwxyz
ABCDEFGHIJKLMNOPQRSTUVWXYZ
0123456789
[0] ['xiahou', 'zuoxin']
'xiahou' int str: True
'xiah' int str: True