Python Functions Notebook

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Notation for errors I met.
For quick search

Build in function

A

assert

code:
assert statement
explanation:

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if statement == True:
    continue
else:
    report AssertionError

R

readline()

read the first line and begin with second line
data:

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Title,Released,Label,UK Chart Position,US Chart Position,BPI Certification,RIAA Certification
Please Please Me,22 March 1963,Parlophone(UK),1,-,Gold,Platinum

code:

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with open(datafile, "r") as f:
    header = f.readline().split(",")
        for line in f:
        ...

header:
['Title', 'Released', 'Label', 'UK Chart Position', 'US Chart Position', 'BPI Certification', 'RIAA Certification\n']
line:
Please Please Me,22 March 1963,Parlophone(UK),1,-,Gold,Platinum

S

strip()

can be used to delete the \n code
code:

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header = f.readline().split(",")
print header
print header[-1]
print header[-1].strip()

output:

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['Title', 'Released', 'Label', 'UK Chart Position', 'US Chart Position', 'BPI Certification', 'RIAA Certification\n']
RIAA Certification
RIAA Certification

Imported modules

csv

csv.DictReader()

read csv file,
default denote the first row as the field labels,
line is dict data type
code:

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import csv
with open(datafile, 'rb') as sd:
    r = csv.DictReader(sd)
    for line in r:
    ...

more details can be found in ud032 Using CSV Module

xlrd

xlrd.open_workbook()

read xls file
code:

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import xlrd
datafile = "2013_ERCOT_Hourly_Load_Data.xls"
workbook = xlrd.open_workbook(datafile)
sheet = workbook.sheet_by_index(0)
data = [[sheet.cell_value(r, col) 
                for col in range(sheet.ncols)] 
                    for r in range(sheet.nrows)]

details can be found in ud032 Notebook

ZipFile

code:

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from zipfile import ZipFile
datafile = "2013_ERCOT_Hourly_Load_Data.xls"