print('1:')

a = 4
b = a
a = 2
print('b =', b)

print('2:')

def f(x,y):
    return 2*x + y

x = 2
y = 3
print(f(1,2))

print('3:')
def f(x):
    return x**2 - 2

y = 2
def g(y):
    return 2*y

y = 4
print(y, g(f(2)))

print('4:')
def H(x):
    if x < 0:
        return 0.0
    else:
        return 1.0

print(H(0.0))

print('5:')
a = 2
b = 3

def sum(a,b):
    return a + b

s = sum(a,a)
a = 4

print(a,s)

print('6:')
a = [4,5]+[1,2,3,4]
print(len(a))
a = [0]*6
print(len(a))
a = list(range(6))
print(len(a))
a = [3*e for e in range(2)]
print(len(a))

print('7:')
s = [1,2,3,4]

for i in range(len(s)):
    s[i] = s[i]**2


print(s[3])

print('8:')
formula = '2*x+4'
x = 2
print(eval(formula))


print('9:')
s = -2
for i in range(2,5,2):
    s += i
print(s)

print('10:')
dx = 0.25
b = [dx*i for i in range(5)]
print(b[-1])


print('11:')
C = -20
dC = 5

Clist = []
Flist = []
while C <= 40:
    Clist.append(C)
    Flist.append(2*C + 30)
    C = C + dC

print(Clist[-1],Flist[-1])

print('12:')
first_names = ['Minch','Han','Luke']
last_names = ['Yoda', 'Solo', 'Skywalker']

names = first_names + last_names

#print(names[len(names)])

print('13:')
import sys

try:
    v0 = 5#float(sys.argv[1])
    g = 9.81#float(sys.argv[2])
except IndexError:
    print('Please provide two command line arguments')
    sys.exit()
except ValueError:
    print('The arguments must be numbers')
    sys.exit()



def y(t,v0,g):
    return v0*t-0.5*g*t**2

print(y(0.6,v0,g))

print('14:')


def volume(x,y,z):
    return x*y*z

def test_volume():
    x = 2.0
    y = 3.0
    z = 4.0
    tol = 1e-8
    success = abs(volume(x,y,z)-24)<tol
    msg = 'Something wrong in volume'
    assert success, msg

test_volume()

print('15:')
for i in range(3):
    for j in range(i):
        if j < i:
            print(i,j, end=' ')



print('\n16:')
import numpy as np
a = np.linspace(0, 2.5, 6)
b = a*2
print(b)

print('17:')
x = 6
y = -2
c = x >= 10 or y != -2

print(c)

print('18:')
def find_max(a):
    max_a = -100
    for e in a:
        if e > max_a:
            max_a = e
    return max_a

a = [0,2,4,5,10,8,3,4,6]
print(find_max(a) == max(a))


print('19:')
line = "All work and no play makes Jack a dull boy"
words = line.split()
print(type(words),type(words[-1]))

print('20:')
#no code

print('21:')
from math import *

def num_diff(f,x,h=1e-6):
    return (f(x+h)-f(x))/h

d = num_diff(sin,pi)
print(d)

print('22:')
import sys
A = [['-1','0','1'],['0','0','0'],['10','9','8']]

try:
    b = int(A[2])
except IndexError:
    print('A has length %d' %len(A))
    sys.exit(1)
except TypeError:
    print('Cannot convert %s to int' %A[2])
    #sys.exit(1)

print(b)

print('23:')
import matplotlib.pyplot as plt
from math import pi

def pi_approx(n):
    a = 0
    for k in range(1,n+1):
        a += (-1)**(k+1)/(2*k-1)
    return 4*a

index_list = range(1,51)
a_list = []
for i in index_list:
    a_list.append(pi_approx(i))
plt.plot(index_list,a_list)
#plt.show()


print('24:')
Clist = []
F = 0
while F < 40:
    Clist.append((F-32)*5.0/9)
    F += 5

print(Clist)
Clist = []
for F in range(0,40,5):
    Clist.append((F-32)*5.0/9)

print(Clist)

print('25:')
infile = open('temperature.dat')
for i in range(2):
    infile.readline()

year = 0
tmax = -100

for line in infile:
    words = line.split()
    temp = float(words[2])
    if temp > tmax:
        tmax = temp
        year = int(words[0])

print(year, tmax)