Python was started in 1989 by "Guido".Python is free and easy to learn.
2017-03-03
d = {
'Adam': 95,
'Lisa': 85,
'Bart': 59
}
temp=0
score=input("分数\n")
for key in d:
if d[key]==int(score):
print (key)
temp=1
break
if temp==0:
print ('None')
'Adam': 95,
'Lisa': 85,
'Bart': 59
}
temp=0
score=input("分数\n")
for key in d:
if d[key]==int(score):
print (key)
temp=1
break
if temp==0:
print ('None')
2017-03-03
d = {
'Adam': 95,
'Lisa': 85,
'Bart': 59
}
#way 01
print ('Adam:'+str(d.get('Adam')))
print ('Lisa:'+str(d.get('Lisa')))
print ('Bart:'+str(d.get('Bart')))
#way 02
for (key,value) in d.items():
print(key+str(value))
#way 03
for (key,value) in d.items():
print(key,value)
'Adam': 95,
'Lisa': 85,
'Bart': 59
}
#way 01
print ('Adam:'+str(d.get('Adam')))
print ('Lisa:'+str(d.get('Lisa')))
print ('Bart:'+str(d.get('Bart')))
#way 02
for (key,value) in d.items():
print(key+str(value))
#way 03
for (key,value) in d.items():
print(key,value)
2017-03-03
for i in range(1, 10):
for j in range(1, 10):
for x in range(1, 10):
if x == i
print i * 100 + j * 10 + x
哪里不对了
for j in range(1, 10):
for x in range(1, 10):
if x == i
print i * 100 + j * 10 + x
哪里不对了
2017-03-03
1. 如果a=0, bx+c=0, x= -c/b
2. 如果a≠0,
ax²+bx+c=0
x²+b/ax+c/a=0
x²+b/ax+b²/4a²=-c/a+b²/4a²
(x+b/2a)²=(b²-4ac)/4a²
2.1 如果b²-4ac<0,则无解。
2.2 如果b²-4ac≥0, 4a²>0
∴x+b/2a=±√(b²-4ac)/2a
x=-b/2a±√(b²-4ac)/2a
即x=[-b±√(b²-4ac)]/2a
2. 如果a≠0,
ax²+bx+c=0
x²+b/ax+c/a=0
x²+b/ax+b²/4a²=-c/a+b²/4a²
(x+b/2a)²=(b²-4ac)/4a²
2.1 如果b²-4ac<0,则无解。
2.2 如果b²-4ac≥0, 4a²>0
∴x+b/2a=±√(b²-4ac)/2a
x=-b/2a±√(b²-4ac)/2a
即x=[-b±√(b²-4ac)]/2a
2017-03-03
L = range(1, 101)
print L[:10]
print L[2::3]
print L[4:50:5]
print L[:10]
print L[2::3]
print L[4:50:5]
2017-03-03