Python Basics
Contents
4+5 +6
15
Python Basics¶
The first notebook of the day
Today’s lesson covers:
notebooks
data analysis
plotting
hello
goodbye
sarah
Variables and Assignment¶
name = 'sarah'
sentence = "Sarah's title is Dr. "
name
'sarah'
sentence
name
'sarah'
last_name
---------------------------------------------------------------------------
NameError Traceback (most recent call last)
/tmp/ipykernel_1795/640889992.py in <module>
----> 1 last_name
NameError: name 'last_name' is not defined
last_name = 'Brown'
last_name
'Brown'
print(name)
sarah
name
'sarah'
4+5
9
age = 34
age
34
age + 5
39
full_name = name + last_name
full_name
'sarahBrown'
name*3
'sarahsarahsarah'
[1,3,4]*4
[1, 3, 4, 1, 3, 4, 1, 3, 4, 1, 3, 4]
name[0]
's'
name[5]
---------------------------------------------------------------------------
IndexError Traceback (most recent call last)
<ipython-input-19-94fccd0ebc6d> in <module>
----> 1 name[5]
IndexError: string index out of range
name[1:3]
'ar'
name[0:4]
'sara'
name[-1]
'h'
my_string = 'NSBE 48 is in Anaheim'
How can you print out only the word Anaheim (7characters)
my_string[-7:]
'Anaheim'
my_string[14:]
'Anaheim'
Notes so far¶
print('before')
print()
print('after')
before
after
Print out what we saw above using only one print call
print('before','after',sep='\n\n')
before
after
print(In [26])
print('before')
print()
print('after')
print?
help(print)
Help on built-in function print in module builtins:
print(...)
print(value, ..., sep=' ', end='\n', file=sys.stdout, flush=False)
Prints the values to a stream, or to sys.stdout by default.
Optional keyword arguments:
file: a file-like object (stream); defaults to the current sys.stdout.
sep: string inserted between values, default a space.
end: string appended after the last value, default a newline.
flush: whether to forcibly flush the stream.
my_string = 'Hello world!'
len(my_string)
12
my_string.upper
<function str.upper()>
my_string.upper()
'HELLO WORLD!'
my_string.swapcase()
'hELLO WORLD!'
my_string.isupper()
False
my_string.upper().isupper()
True
remaing = 100-age
remaing
66
name*3
'sarahsarahsarah'
4*5
20
import math
math.pi
3.141592653589793
math.e
2.718281828459045
help(math)
Help on module math:
NAME
math
MODULE REFERENCE
https://docs.python.org/3.8/library/math
The following documentation is automatically generated from the Python
source files. It may be incomplete, incorrect or include features that
are considered implementation detail and may vary between Python
implementations. When in doubt, consult the module reference at the
location listed above.
DESCRIPTION
This module provides access to the mathematical functions
defined by the C standard.
FUNCTIONS
acos(x, /)
Return the arc cosine (measured in radians) of x.
acosh(x, /)
Return the inverse hyperbolic cosine of x.
asin(x, /)
Return the arc sine (measured in radians) of x.
asinh(x, /)
Return the inverse hyperbolic sine of x.
atan(x, /)
Return the arc tangent (measured in radians) of x.
atan2(y, x, /)
Return the arc tangent (measured in radians) of y/x.
Unlike atan(y/x), the signs of both x and y are considered.
atanh(x, /)
Return the inverse hyperbolic tangent of x.
ceil(x, /)
Return the ceiling of x as an Integral.
This is the smallest integer >= x.
comb(n, k, /)
Number of ways to choose k items from n items without repetition and without order.
Evaluates to n! / (k! * (n - k)!) when k <= n and evaluates
to zero when k > n.
Also called the binomial coefficient because it is equivalent
to the coefficient of k-th term in polynomial expansion of the
expression (1 + x)**n.
Raises TypeError if either of the arguments are not integers.
Raises ValueError if either of the arguments are negative.
copysign(x, y, /)
Return a float with the magnitude (absolute value) of x but the sign of y.
On platforms that support signed zeros, copysign(1.0, -0.0)
returns -1.0.
cos(x, /)
Return the cosine of x (measured in radians).
cosh(x, /)
Return the hyperbolic cosine of x.
degrees(x, /)
Convert angle x from radians to degrees.
dist(p, q, /)
Return the Euclidean distance between two points p and q.
The points should be specified as sequences (or iterables) of
coordinates. Both inputs must have the same dimension.
Roughly equivalent to:
sqrt(sum((px - qx) ** 2.0 for px, qx in zip(p, q)))
erf(x, /)
Error function at x.
erfc(x, /)
Complementary error function at x.
exp(x, /)
Return e raised to the power of x.
expm1(x, /)
Return exp(x)-1.
This function avoids the loss of precision involved in the direct evaluation of exp(x)-1 for small x.
fabs(x, /)
Return the absolute value of the float x.
factorial(x, /)
Find x!.
Raise a ValueError if x is negative or non-integral.
floor(x, /)
Return the floor of x as an Integral.
This is the largest integer <= x.
fmod(x, y, /)
Return fmod(x, y), according to platform C.
x % y may differ.
frexp(x, /)
Return the mantissa and exponent of x, as pair (m, e).
m is a float and e is an int, such that x = m * 2.**e.
If x is 0, m and e are both 0. Else 0.5 <= abs(m) < 1.0.
fsum(seq, /)
Return an accurate floating point sum of values in the iterable seq.
Assumes IEEE-754 floating point arithmetic.
gamma(x, /)
Gamma function at x.
gcd(x, y, /)
greatest common divisor of x and y
hypot(...)
hypot(*coordinates) -> value
Multidimensional Euclidean distance from the origin to a point.
Roughly equivalent to:
sqrt(sum(x**2 for x in coordinates))
For a two dimensional point (x, y), gives the hypotenuse
using the Pythagorean theorem: sqrt(x*x + y*y).
For example, the hypotenuse of a 3/4/5 right triangle is:
>>> hypot(3.0, 4.0)
5.0
isclose(a, b, *, rel_tol=1e-09, abs_tol=0.0)
Determine whether two floating point numbers are close in value.
rel_tol
maximum difference for being considered "close", relative to the
magnitude of the input values
abs_tol
maximum difference for being considered "close", regardless of the
magnitude of the input values
Return True if a is close in value to b, and False otherwise.
For the values to be considered close, the difference between them
must be smaller than at least one of the tolerances.
-inf, inf and NaN behave similarly to the IEEE 754 Standard. That
is, NaN is not close to anything, even itself. inf and -inf are
only close to themselves.
isfinite(x, /)
Return True if x is neither an infinity nor a NaN, and False otherwise.
isinf(x, /)
Return True if x is a positive or negative infinity, and False otherwise.
isnan(x, /)
Return True if x is a NaN (not a number), and False otherwise.
isqrt(n, /)
Return the integer part of the square root of the input.
ldexp(x, i, /)
Return x * (2**i).
This is essentially the inverse of frexp().
lgamma(x, /)
Natural logarithm of absolute value of Gamma function at x.
log(...)
log(x, [base=math.e])
Return the logarithm of x to the given base.
If the base not specified, returns the natural logarithm (base e) of x.
log10(x, /)
Return the base 10 logarithm of x.
log1p(x, /)
Return the natural logarithm of 1+x (base e).
The result is computed in a way which is accurate for x near zero.
log2(x, /)
Return the base 2 logarithm of x.
modf(x, /)
Return the fractional and integer parts of x.
Both results carry the sign of x and are floats.
perm(n, k=None, /)
Number of ways to choose k items from n items without repetition and with order.
Evaluates to n! / (n - k)! when k <= n and evaluates
to zero when k > n.
If k is not specified or is None, then k defaults to n
and the function returns n!.
Raises TypeError if either of the arguments are not integers.
Raises ValueError if either of the arguments are negative.
pow(x, y, /)
Return x**y (x to the power of y).
prod(iterable, /, *, start=1)
Calculate the product of all the elements in the input iterable.
The default start value for the product is 1.
When the iterable is empty, return the start value. This function is
intended specifically for use with numeric values and may reject
non-numeric types.
radians(x, /)
Convert angle x from degrees to radians.
remainder(x, y, /)
Difference between x and the closest integer multiple of y.
Return x - n*y where n*y is the closest integer multiple of y.
In the case where x is exactly halfway between two multiples of
y, the nearest even value of n is used. The result is always exact.
sin(x, /)
Return the sine of x (measured in radians).
sinh(x, /)
Return the hyperbolic sine of x.
sqrt(x, /)
Return the square root of x.
tan(x, /)
Return the tangent of x (measured in radians).
tanh(x, /)
Return the hyperbolic tangent of x.
trunc(x, /)
Truncates the Real x to the nearest Integral toward 0.
Uses the __trunc__ magic method.
DATA
e = 2.718281828459045
inf = inf
nan = nan
pi = 3.141592653589793
tau = 6.283185307179586
FILE
/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/lib-dynload/math.cpython-38-darwin.so
help(math.pi)
Help on float object:
class float(object)
| float(x=0, /)
|
| Convert a string or number to a floating point number, if possible.
|
| Methods defined here:
|
| __abs__(self, /)
| abs(self)
|
| __add__(self, value, /)
| Return self+value.
|
| __bool__(self, /)
| self != 0
|
| __divmod__(self, value, /)
| Return divmod(self, value).
|
| __eq__(self, value, /)
| Return self==value.
|
| __float__(self, /)
| float(self)
|
| __floordiv__(self, value, /)
| Return self//value.
|
| __format__(self, format_spec, /)
| Formats the float according to format_spec.
|
| __ge__(self, value, /)
| Return self>=value.
|
| __getattribute__(self, name, /)
| Return getattr(self, name).
|
| __getnewargs__(self, /)
|
| __gt__(self, value, /)
| Return self>value.
|
| __hash__(self, /)
| Return hash(self).
|
| __int__(self, /)
| int(self)
|
| __le__(self, value, /)
| Return self<=value.
|
| __lt__(self, value, /)
| Return self<value.
|
| __mod__(self, value, /)
| Return self%value.
|
| __mul__(self, value, /)
| Return self*value.
|
| __ne__(self, value, /)
| Return self!=value.
|
| __neg__(self, /)
| -self
|
| __pos__(self, /)
| +self
|
| __pow__(self, value, mod=None, /)
| Return pow(self, value, mod).
|
| __radd__(self, value, /)
| Return value+self.
|
| __rdivmod__(self, value, /)
| Return divmod(value, self).
|
| __repr__(self, /)
| Return repr(self).
|
| __rfloordiv__(self, value, /)
| Return value//self.
|
| __rmod__(self, value, /)
| Return value%self.
|
| __rmul__(self, value, /)
| Return value*self.
|
| __round__(self, ndigits=None, /)
| Return the Integral closest to x, rounding half toward even.
|
| When an argument is passed, work like built-in round(x, ndigits).
|
| __rpow__(self, value, mod=None, /)
| Return pow(value, self, mod).
|
| __rsub__(self, value, /)
| Return value-self.
|
| __rtruediv__(self, value, /)
| Return value/self.
|
| __sub__(self, value, /)
| Return self-value.
|
| __truediv__(self, value, /)
| Return self/value.
|
| __trunc__(self, /)
| Return the Integral closest to x between 0 and x.
|
| as_integer_ratio(self, /)
| Return integer ratio.
|
| Return a pair of integers, whose ratio is exactly equal to the original float
| and with a positive denominator.
|
| Raise OverflowError on infinities and a ValueError on NaNs.
|
| >>> (10.0).as_integer_ratio()
| (10, 1)
| >>> (0.0).as_integer_ratio()
| (0, 1)
| >>> (-.25).as_integer_ratio()
| (-1, 4)
|
| conjugate(self, /)
| Return self, the complex conjugate of any float.
|
| hex(self, /)
| Return a hexadecimal representation of a floating-point number.
|
| >>> (-0.1).hex()
| '-0x1.999999999999ap-4'
| >>> 3.14159.hex()
| '0x1.921f9f01b866ep+1'
|
| is_integer(self, /)
| Return True if the float is an integer.
|
| ----------------------------------------------------------------------
| Class methods defined here:
|
| __getformat__(typestr, /) from builtins.type
| You probably don't want to use this function.
|
| typestr
| Must be 'double' or 'float'.
|
| It exists mainly to be used in Python's test suite.
|
| This function returns whichever of 'unknown', 'IEEE, big-endian' or 'IEEE,
| little-endian' best describes the format of floating point numbers used by the
| C type named by typestr.
|
| __set_format__(typestr, fmt, /) from builtins.type
| You probably don't want to use this function.
|
| typestr
| Must be 'double' or 'float'.
| fmt
| Must be one of 'unknown', 'IEEE, big-endian' or 'IEEE, little-endian',
| and in addition can only be one of the latter two if it appears to
| match the underlying C reality.
|
| It exists mainly to be used in Python's test suite.
|
| Override the automatic determination of C-level floating point type.
| This affects how floats are converted to and from binary strings.
|
| fromhex(string, /) from builtins.type
| Create a floating-point number from a hexadecimal string.
|
| >>> float.fromhex('0x1.ffffp10')
| 2047.984375
| >>> float.fromhex('-0x1p-1074')
| -5e-324
|
| ----------------------------------------------------------------------
| Static methods defined here:
|
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
|
| ----------------------------------------------------------------------
| Data descriptors defined here:
|
| imag
| the imaginary part of a complex number
|
| real
| the real part of a complex number
math.cos(2*math.pi)
1.0
from math import cos, pi
cos(pi)
-1.0
import math as m
m.sin(m.pi)
1.2246467991473532e-16
Put these in order:
bases="ACTTGCTTGAC"
import math
import random
___ = random.randrange(n_bases)
___ = len(bases)
print("random base ", bases[___], "base index", ___)
# this is a comment
# import the libraries
import math
import random
# list of bases
bases="ACTTGCTTGAC"
# number of bases
n_bases= len(bases)
# sample a random integer from 0 to the number of bases
rand_index = random.randrange(n_bases)
# print by selecting the random index
# and print out that number too
print("random base ", bases[rand_index], "base index", rand_index)
random base G base index 8
bases[8]
'G'