lab one one | Python Fiddle

# C.1.1 9 - 3 -->; 6
# C.1.2 8 * 2.5 -->; 20
# C.1.3 9 / 2 -->; 4
# C.1.4 9 / -2 -->; -5
# C.1.5 9 % 2 -->; 1
# C.1.6 9 % -2 -->; -1
# C.1.7 -9 % 2 -->; 1
# C.1.8 9 / -2.0 -->; -4.5
# C.1.9 4 + 3 * 5 -->; 19
# C.1.10 (4 + 3) * 5 -->; 60

# C.2.1 print x -->; 100
# C.2.2 print x -->; 110
# C.2.3 print x -->; 130
# C.2.4 print x -->; 90
# C.2.5 print x -->; 40
# C.2.6 print x -->; 120
# C.2.7 print x -->; 24
# C.2.8 print x -->; 0

# C.3 x += x - x
    # x += (x - x) Python sees it has to evalutate the expression that the operator is to add to x
    # x += (3 - 3) Pyhton fills in the value for x, and evaluates it
    # x += 0
    # x = x + 0    Python evaluates the operator
    # x = x
    # x = 3
    # print x -->; 3

# C.4.1 1j + 2.4j -->; 3.4j
# C.4.2 4j * 4j -->; (-16+0j)
# C.4.3 (1+2j) / (3+4j) -->; (0.44+0.08j)
# C.4.1 (1+2j) * (1+2j) -->; (-3+4j)
# C.4.2 1+2j * 1+2j -->; (1+4j)
    # In the second version, python evaluates the multiplication first, and the the addition (This is why python always puts results of
    # complex math operations in parentheses) Python doesn't consider a complex number to be anything different from the sum of two real
    # numbers.

# C.5.1 cmath.sin(-1.0+2.0j) -->; (-3.16577851322+1.95960104142j)
# C.5.2 cmath.log(-1.0+3.4j) -->; (0.804718956217+2.0344439358j)
# C.5.3 cmath.exp(-cmath.pi * 1.0j) -->; (-1+0j) (Actual output is (-1-1.22464679915e-16j) due to lack of floating point precision in the
    # cmath.exp function.)
# C.5.4 cmath and math have tons of functions in common (sin, cos, exp, log, etc...) which would cause lots of name clashes that could
    # lead to subtle bugs.

# C.6.1 "foo" + 'bar' -->; 'foobar'
# C.6.2 "foo" 'bar' -->; 'foobar'
# C.6.3 a + b -->; 'foobar'
# C.6.4 a b -->;     print a b
#                            ^
#                  SyntaxError: invalid syntax

# C.7 'A\nB\nC'

# C.8
print 80* '-'

# C.9 'first line\nsecond line\nthird line'

# C.10
x=3
y=12.5
print 'The rabbit is %d.' % x
print 'The rabbit is %d years old.' % x
print '%.1f is average.' % y
print '%.1f * %d' % (y,x)
print '%.1f * %d is %.3g' % (y,x,x*y)

# C.11
num = float(raw_input("Enter a number: "))
print num

# C.12
def quadratic(a,b,c,x):
    return a * x ** 2 + b * x + c
#If you didn't use '**' as a power operator, you could just do 'a * x * x'

# C.13
def GC_content(dnastr):
    '''Converts a string of DNA information into a percentage representing the GC content of the DNA base pairs, as a floating point number'''
    return (float(dnastr.count('G')) + float(dnastr.count('C'))) / float(len(list(dnastr)))

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