week 8 intro to functions Flashcards
def keyword
defines the function, the statement has color at the end and indented function body
how can you customize a function?
add parameters so that numbers/vars can be passed as arguments in function call
3 steps of making a function
1) define (fun name, parameters, body)
2) call (pass arguments)
3) execute (use parameters to compute result)
find method
returns indices of first instance of a substring
string slicing
extracting certain characters (1st number inclusive, 2nd number exclusive)
split method
splits string into list based on specified delimeter
local variable
only exists in the function, the function is an ‘island’
global variable
exists and modified in main code
pass by value
parameters changed in function does not affect variables outside the function
return function
outputs value from function
copy paste error
forgetting to modify code after pasting into new environment
return error
accidentally returning the wrong variable or forgetting to add return statement
unpacking
operation that allows statement to perform multiple assignments at once (ex: assigning tuple/list to variable in one line)
index
integer matching specific position in ordered object (list, tuple, etc) starts at 0 and uses brackets to index
slice notation
allows selection of multiple indices per list (using colons to select all before, after, or in between integers) negative numbers means a step back from the end
slicing operation
if you assign a slice to a var and reassign the original string, the slice var will stay the same
stride
step size to increment index
my_str[0:10:2]
0 to 10 in steps of 2 (every other, starting at 0)
field width
defines minimum number of characters inserted in string, any extra space is padded with spaces to reach that minimum value
{name:16}
field width of 16 characters
alignment character
determines how value should be aligned within width of field
<
left aligned
>
right aligned
center aligned
fill character
you can pad with a specific character, like 0s
{score:0>4}
pad with zeros, right aligned, field width of 4
percision
number of places after the decimal point (rounds)
{1.725:.1f}
1.7
replace(old, new)
returns copy of string with all occurances of old replaced with new
replace(old, new, count)
returns copy of string with first COUNT occurances of old replaced with new
find(x)
returns index of first occurance of x
find(x, start)
returns index of first occurance of x from index start onwards
find(x, start, end)
returns index of first occurance of x between start and end index
rfind(x)
returns index of first occurance backwards( searches string in reverse)
count(x)
counts number of occurances of X
string comparisons
compares ASCII number of 1st elements, if everything is the same the shorter string is less than the alrger
is/is not
compares object types, not values
isalnum()
true if chars are letter or number
isdigit()
true if chars are numbers
startswith(x)
true if string starts with x
endswith(x)
true if string ends with x
capitalize()
capitalizes first character of string
strip()
removes all whitespace at start and end of string
title()
makes starting title with each word capitalized
split()
split string into list of tokens
token
substring that forms part of a larger string
separator
character or sequence that indicates where string splits into tokens, if there’s a double separator then that list item is empty quotes
join method
inverse of split, joins list of strings based on delimeter
’‘.join(x)
x is the list and the delimeter to join is ‘’
