In [30]:
import numpy

In [31]:
import matplotlib.pyplot

In [ ]:


In [32]:
%matplotlib inline

In [33]:
data = numpy.loadtxt (fname = 'data/weather-01.csv' , delimiter = ',')

In [34]:
# Create a wide figure to hold the subplots
fig = matplotlib.pyplot.figure (figsize=(10.0, 3.0))

# create placeholders for plots
subplot1 = fig.add_subplot (1,3,1)
subplot2 = fig.add_subplot (1,3,2)
subplot3 = fig.add_subplot (1,3,3)

subplot1.set_ylabel('average')
subplot1.plot(numpy.mean(data, axis=0))

subplot2.set_ylabel('max')
subplot2.plot(numpy.max(data, axis=0))

subplot3.set_ylabel('min')
subplot3.plot(numpy.min(data, axis=0))

fig.tight_layout()
matplotlib.pyplot.show


Out[34]:
<function matplotlib.pyplot.show>

In [35]:
# create placeholders for plots
subplot1 = fig.add_subplot (1,3,1)
subplot2 = fig.add_subplot (1,3,2)
subplot3 = fig.add_subplot (1,3,3)

Loops


In [36]:
word = 'notebook'
print (word[4])


b

In [37]:
for char in word: 
    print (char)


n
o
t
e
b
o
o
k

Get a list of all the filenames from disk


In [38]:
import glob

In [39]:
print (glob.glob('data/weather*.csv'))


['data\\weather-01.csv', 'data\\weather-02.csv', 'data\\weather-03.csv', 'data\\weather-04.csv', 'data\\weather-05.csv', 'data\\weather-06.csv', 'data\\weather-07.csv', 'data\\weather-08.csv', 'data\\weather-09.csv', 'data\\weather-10.csv', 'data\\weather-11.csv', 'data\\weather-12.csv']

Putting it all together


In [40]:
filenames = sorted(glob.glob('data/weather*.csv'))
filenames = filenames[0:12]

for f in filenames:
    print (f)
    
    data = numpy.loadtxt(fname=f, delimiter=',')
    
    if numpy.max (data, axis=0)[0] == 0 and numpy.max (data, axis=0)[20] ==20:
        print ("Suspicous looking maximum")
    elif numpy.sum(numpy.min(data, axis=0)) == 0:
        print ("Minimum add up to zero")
    else:
        print ("Data looks OK")

    # Create a wide figure to hold the subplots
    fig = matplotlib.pyplot.figure (figsize=(10.0, 3.0))

    # create placeholders for plots
    subplot1 = fig.add_subplot (1,3,1)
    subplot2 = fig.add_subplot (1,3,2)
    subplot3 = fig.add_subplot (1,3,3)

    subplot1.set_ylabel('average')
    subplot1.plot(numpy.mean(data, axis=0))

    subplot2.set_ylabel('max')
    subplot2.plot(numpy.max(data, axis=0))

    subplot3.set_ylabel('min')
    subplot3.plot(numpy.min(data, axis=0))

    fig.tight_layout()
    matplotlib.pyplot.show


data\weather-01.csv
Suspicous looking maximum
data\weather-02.csv
Suspicous looking maximum
data\weather-03.csv
Minimum add up to zero
data\weather-04.csv
Suspicous looking maximum
data\weather-05.csv
Suspicous looking maximum
data\weather-06.csv
Suspicous looking maximum
data\weather-07.csv
Suspicous looking maximum
data\weather-08.csv
Minimum add up to zero
data\weather-09.csv
Suspicous looking maximum
data\weather-10.csv
Suspicous looking maximum
data\weather-11.csv
Minimum add up to zero
data\weather-12.csv
Suspicous looking maximum

Making decisions


In [41]:
num = 107
if num > 100: 
    print ('Greater')
else:
    print ('Not greater')
    print ('Done')


Greater

In [42]:
num = 6
if num > 0:
    print (num, "is positive")
elif num == 0:
    print (num, "is zero")
else:
    print (num, "is negative")


6 is positive

Functions


In [43]:
def fahr_to_kelvin(temp):
    return ((temp - 32) * (5/9) + 273.15)

In [44]:
print ('Freezing point of water: ', fahr_to_kelvin(32))


Freezing point of water:  273.15

In [45]:
print ('Boiling point of water: ', fahr_to_kelvin(212))


Boiling point of water:  373.15

In [46]:
def analyse (filename):
    data = numpy.loadtxt(fname=filename, delimiter=',')
    
    """This function analyses the temperature data and plots it into three separate subplots which contain the average
    maximum and minimum temperature data, respectively"""
    
    # Create a wide figure to hold the subplots
    fig = matplotlib.pyplot.figure (figsize=(10.0, 3.0))

    # create placeholders for plots
    subplot1 = fig.add_subplot (1,3,1)
    subplot2 = fig.add_subplot (1,3,2)
    subplot3 = fig.add_subplot (1,3,3)

    subplot1.set_ylabel('average')
    subplot1.plot(numpy.mean(data, axis=0))

    subplot2.set_ylabel('max')
    subplot2.plot(numpy.max(data, axis=0))

    subplot3.set_ylabel('min')
    subplot3.plot(numpy.min(data, axis=0))

    fig.tight_layout()
    matplotlib.pyplot.show

In [47]:
def detect_problems (filename):
    """Some of our temperature files have problems, check for these
    
        This function reads a file (filename argument) and reports on odd looking maxima and minima that add up to zero. 
        This seems to happen when the sensors break. The function does not return any data.
    """
    data = numpy.loadtxt(fname=filename, delimiter=',')
    
    if numpy.max (data, axis=0)[0] == 0 and numpy.max (data, axis=0)[20] ==20:
        print ("Suspicous looking maximum")
    elif numpy.sum(numpy.min(data, axis=0)) == 0:
        print ("Minimum add up to zero")
    else:
        print ("Data looks OK")

In [48]:
for f in filenames [0:5]:
    print (f)
    analyse (f)
    detect_problems (f)


data\weather-01.csv
Suspicous looking maximum
data\weather-02.csv
Suspicous looking maximum
data\weather-03.csv
Minimum add up to zero
data\weather-04.csv
Suspicous looking maximum
data\weather-05.csv
Suspicous looking maximum

In [49]:
help(numpy.loadtxt)


Help on function loadtxt in module numpy.lib.npyio:

loadtxt(fname, dtype=<class 'float'>, comments='#', delimiter=None, converters=None, skiprows=0, usecols=None, unpack=False, ndmin=0)
    Load data from a text file.
    
    Each row in the text file must have the same number of values.
    
    Parameters
    ----------
    fname : file or str
        File, filename, or generator to read.  If the filename extension is
        ``.gz`` or ``.bz2``, the file is first decompressed. Note that
        generators should return byte strings for Python 3k.
    dtype : data-type, optional
        Data-type of the resulting array; default: float.  If this is a
        structured data-type, the resulting array will be 1-dimensional, and
        each row will be interpreted as an element of the array.  In this
        case, the number of columns used must match the number of fields in
        the data-type.
    comments : str or sequence, optional
        The characters or list of characters used to indicate the start of a
        comment;
        default: '#'.
    delimiter : str, optional
        The string used to separate values.  By default, this is any
        whitespace.
    converters : dict, optional
        A dictionary mapping column number to a function that will convert
        that column to a float.  E.g., if column 0 is a date string:
        ``converters = {0: datestr2num}``.  Converters can also be used to
        provide a default value for missing data (but see also `genfromtxt`):
        ``converters = {3: lambda s: float(s.strip() or 0)}``.  Default: None.
    skiprows : int, optional
        Skip the first `skiprows` lines; default: 0.
    usecols : sequence, optional
        Which columns to read, with 0 being the first.  For example,
        ``usecols = (1,4,5)`` will extract the 2nd, 5th and 6th columns.
        The default, None, results in all columns being read.
    unpack : bool, optional
        If True, the returned array is transposed, so that arguments may be
        unpacked using ``x, y, z = loadtxt(...)``.  When used with a structured
        data-type, arrays are returned for each field.  Default is False.
    ndmin : int, optional
        The returned array will have at least `ndmin` dimensions.
        Otherwise mono-dimensional axes will be squeezed.
        Legal values: 0 (default), 1 or 2.
    
        .. versionadded:: 1.6.0
    
    Returns
    -------
    out : ndarray
        Data read from the text file.
    
    See Also
    --------
    load, fromstring, fromregex
    genfromtxt : Load data with missing values handled as specified.
    scipy.io.loadmat : reads MATLAB data files
    
    Notes
    -----
    This function aims to be a fast reader for simply formatted files.  The
    `genfromtxt` function provides more sophisticated handling of, e.g.,
    lines with missing values.
    
    .. versionadded:: 1.10.0
    
    The strings produced by the Python float.hex method can be used as
    input for floats.
    
    Examples
    --------
    >>> from io import StringIO   # StringIO behaves like a file object
    >>> c = StringIO("0 1\n2 3")
    >>> np.loadtxt(c)
    array([[ 0.,  1.],
           [ 2.,  3.]])
    
    >>> d = StringIO("M 21 72\nF 35 58")
    >>> np.loadtxt(d, dtype={'names': ('gender', 'age', 'weight'),
    ...                      'formats': ('S1', 'i4', 'f4')})
    array([('M', 21, 72.0), ('F', 35, 58.0)],
          dtype=[('gender', '|S1'), ('age', '<i4'), ('weight', '<f4')])
    
    >>> c = StringIO("1,0,2\n3,0,4")
    >>> x, y = np.loadtxt(c, delimiter=',', usecols=(0, 2), unpack=True)
    >>> x
    array([ 1.,  3.])
    >>> y
    array([ 2.,  4.])


In [50]:
help(detect_problems)


Help on function detect_problems in module __main__:

detect_problems(filename)
    Some of our temperature files have problems, check for these
    
    This function reads a file (filename argument) and reports on odd looking maxima and minima that add up to zero. 
    This seems to happen when the sensors break. The function does not return any data.


In [51]:
help(detect_problems)


Help on function detect_problems in module __main__:

detect_problems(filename)
    Some of our temperature files have problems, check for these
    
    This function reads a file (filename argument) and reports on odd looking maxima and minima that add up to zero. 
    This seems to happen when the sensors break. The function does not return any data.


In [52]:
help(detect_problems)


Help on function detect_problems in module __main__:

detect_problems(filename)
    Some of our temperature files have problems, check for these
    
    This function reads a file (filename argument) and reports on odd looking maxima and minima that add up to zero. 
    This seems to happen when the sensors break. The function does not return any data.


In [53]:
help(analyse)


Help on function analyse in module __main__:

analyse(filename)


In [54]:
help(analyse)


Help on function analyse in module __main__:

analyse(filename)


In [ ]: