python基础（二）
#条件判断
#布尔变量条件判断方法
not True # False
not False #True
True and False #False
True or False #True
True == False #False
True != False #True
True > False #True
True >= False #True
True < False #False
True <= False #False
True is False #False
True is True #True
False < True <=True #True
False < True < True #False
#数字条件判断
0 and 2 # 0
0 or -2 # -2
not 2 #False
not 0 #True
not -1 #False
-2 < 3 < 2 #False
0 == False #True
1 == True #true
2 == True #False
0 is False #False
1 is True #False
#python小坑之逻辑判断
# == != > >= < <= 计算的时候是用数值进行计算，但是输出结果是一个布尔值
# not 计算用布尔，结果输出布尔
# is 不计算，只用来判断
# 链式判断大小关系，结果与数学上保持一致
# and从左向右找零或者False，找到立即返回，没找到则返回最后一个
# or 从左往右找非零或者True,找到立即返回，没找到返回最后一个# and
1 and 2 and 3 # 3
1 and True and 3 # 3
1 and 2 and True # True
1 and 0 and 3 # 0
1 and False and 3 # False
0 and False and 3 # False
False and 0 and 3 # False# or
3 or 2 or 1 # 3
0 or 2 or 1 # 2
False or 0 or 1 #1
0 or False or -3#-3
0 or False or False #False
0 or False or 0 # 0
# if 语句
age = input('please enter your age:')
age = int(age)
if age >= 18:
print('your age is:',age)
print('adult')
elif age >= 0:
print('your age is:',age)
print('teenager')
else:
print('input error')
# 循环语句
# for
xList = ['a','b','c','d']
s = ''
for x in xList:
s += x
print(x)
print(s)a = list(range(5))
b = list(range(1,5))
c = list(range(1,5,2))
print(a)
print(b)
print(c)L = list(range(101))
print(len(L))
print(L)
s = 0;
for i in L:
s += i
print(s)
# while 循环 (只要条件满足则持续操作)
n = 1
s = 0;
while n<101:
s += n
n += 1
print(s)a = 1
b = 0;
while True:
b += a
a += 1
if a > 100:
break
print(b)c = 0
d = 0
while True:
c += 1
if c%2 == 1:
continue
if c>101:
break
d += c
print(d)
#内置函数
abs(-2)
min([1,2,3])
max(['s','f','c'])
int(True)
float(-2)
#自定义函数
def my_fun1(a,b):
if a > b:
return a
else:
return b#函数可以返回多个值
def my_func2(a,b):
if a > b:
return a,b
else:
return b,a
#函数的默认参数
def my_funMax(a,b=0):
if a > b:
return a
else:
return b
if __name__ == '__main__':
# assert my_fun1(1,2)==2
# assert my_fun1(4,3)==4
# assert my_func3(4,3)==(4,3)
# assert my_func3(3,4)==(4,3)
assert my_funMax(3,4)==4
assert my_funMax(3)==3print('ok')
