文档介绍：: .
1 你好
.
'''
5 字符串
比起 C/C++,Python .
#! /usr/bin/python
word="abcdefg"
a=word[2]
print ("a is: "+a)
b=word[1:3]
print ("b is: "+b) # index 1 and 2 elements of word.
c=word[:2]
print ("c is: "+c) # index 0 and 1 elements of word.
d=word[0:]
print ("d is: "+d) # All elements of word.
e=word[:2]+word[2:]
print ("e is: "+e) # All elements of word.
f=word[-1]
print ("f is: "+f) # The last elements of word.
g=word[-4:-2]
print ("g is: "+g) # index 3 and 4 elements of word.
h=word[-2:]
print ("h is: "+h) # The last two elements.
i=word[:-2]
print ("i is: "+i) # Everything except the last two charactersl=len(word)
print ("Length of word is: "+ str(l))
中文和英文的字符串长度是否一样?
#! /usr/bin/python
# -*- coding: utf8 -*-
s=input("输入你的中文名,按回车继续");
print ("你的名字是 : " +s)
l=len(s)
print ("你中文名字的长度是:"+str(l))
知识点:
类似 Java,在 python3 里所有字符串都是 unicode,所以长度一致.
6 条件和循环语句
#! /usr/bin/python
#条件和循环语句
x=int(input("Please enter an integer:"))
if x<0:
x=0
print ("Negative changed to zero")
elif x==0:
print ("Zero")
else:
print ("More")
# Loops List
a = ['cat', 'window', 'defenestrate']
for x in a:
print (x, len(x))
#知识点:
# * 条件和循环语句
# * 如何得到控制台输入
7 函数#! /usr/bin/python
# -*- coding: utf8 -*-
def sum(a,b):
return a+b
func = sum
r = func(5,6)
print (r)
# 提供默认值
def add(a,b=2):
return a+b
r=add(1)
print (r)
r=add(1,5)
print (r)
一个好用的函数
#! /usr/bin/python
# -*- coding: utf8 -*-
# The range() function
a =range (1,10)
for i in a:
print (i)
a = range(-2,-11,-3) # The 3rd parameter stands for step
for i in a:
print (i)
知识点:
Python 不用{}来控制程序结构,他强迫你用缩进来写程序,使代码清晰.
定义函数方便简单
方便好用的 range 函数
8 异常处理