tricks I learned today:
1. use 'LOAD LOCAL INFILE'
2. 'SET AUTOCOMMIT=0' - and manually commit at the end.
MATLAB applications, tutorials, examples, tricks, resources,...and a little bit of everything I learned ...
Friday, June 14, 2019
Friday, March 15, 2019
Python function: check if an object is an float
def isfloat(value):
try:
float(value)
return True
except ValueError:
return False
Thursday, March 14, 2019
Python function: format dollars
def format_dollar(s):
"""takes in a str or a number and format it as dollar format
i.e. u'24567.0' --> u'$24,567'
"""
s = str(s) # in case input is not string
try:
i = int(s.split('.')[0])
output = "$" + "{:,}".format(i)
except:
output = s
return output
"""takes in a str or a number and format it as dollar format
i.e. u'24567.0' --> u'$24,567'
"""
s = str(s) # in case input is not string
try:
i = int(s.split('.')[0])
output = "$" + "{:,}".format(i)
except:
output = s
return output
Tuesday, February 5, 2019
AWK: single quote eche line and add comma in the end
File.csv looks like:
line1
line2
line3
Use:
cat file.csv | awk -v a="'" '{print a$0a ","}'
to make it look like:
'line1',
'line2',
'line3',
line1
line2
line3
Use:
cat file.csv | awk -v a="'" '{print a$0a ","}'
to make it look like:
'line1',
'line2',
'line3',
Thursday, January 10, 2019
Python: Notes on Fluent Python
1.
2. List comprehension
a = [['-'] * 3 for i in range(3)]
b = [['-']*3] *3
What is the difference between a and b?
3. Inplace method
Inplace method returns None and does not create a new object. For example:
lst = [5,4,3,2,1]
lst.sort() # return None
4. Sort a list of strings by length
fruits = ['apple', 'grape', 'orange', 'banaba', 'dragon fruit']
sorted(fruits, key=len)
5. recursion
def factorial(n):
return 1 if n<2 else="" factorial="" n-1="" n="" p="">print(factorial(5))
6. from operator import itemgetter, attrgetter, methodcaller
2. List comprehension
a = [['-'] * 3 for i in range(3)]
b = [['-']*3] *3
What is the difference between a and b?
3. Inplace method
Inplace method returns None and does not create a new object. For example:
lst = [5,4,3,2,1]
lst.sort() # return None
4. Sort a list of strings by length
fruits = ['apple', 'grape', 'orange', 'banaba', 'dragon fruit']
sorted(fruits, key=len)
5. recursion
def factorial(n):
return 1 if n<2 else="" factorial="" n-1="" n="" p="">print(factorial(5))
6. from operator import itemgetter, attrgetter, methodcaller
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