Section 1
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str/arr.reverse
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Last updated
6 years ago
Date created
Mar 1, 2020
Cards (65)
Section 1
(50 cards)
str/arr.reverse
evaluates to new reversed version of string or array
while condition
loop that stops when condition evaluates to false, must be ended with end
arr.join("")
will make a string of an array by adding the string in split between elements of the array
<<
shovel in new element to end of array
create a new method
def method (param1, param2, ...) body of method return # desired value end
conditionals
if #elsifs if needed elsif elsif elsif #else after if and all elsifs if needed else (encompasses all non if/elsif conditions)
>=
check if one number is greater than/equal to another
create empty array
arr = []
/
divide two numbers
str/arr[startIdx..endIdx]
will return a new string/array with elements from startIdx to endIdx (inclusive)
<
check if one number is less than another
str/arr.reverse!
changes str/arr to its reversed version
<=
check if one number is less than/equal to another
str.index(" ")
returns starting index of quoted string
next
skips to the next iteration of a loop
%
get remainder of two numbers
create empty string
str = ()
str.split("")
will split up the string into an array of multiple strings by separating at the string in split
!=
check if two elements do not equal one another
str/arr[startIdx...endIdx]
will return a new string/array with elements from startIdx to endIdx (not including the char/ele at endIdx)
break
immediately exits loop
create empty hash
hsh = {}
x += n
replaces the value of variable x with the value x+n
.pop
takes in no parameters, removes last element of an array. evaluates to that element.
iteration
what we call each cycle of a loop
.shift
takes in no parameters, removes first element in an array. evaluates to that element.
calling a method with no parameters
just type method with no parentheses
negative indices
will evaluate to ele/char starting at end of array/string, where arr[-1]/str[-1] evaluate to the final element/character respectively
.length
returns length of string returns size of array returns number of key/value pairs in hash
str.include?(" ")
returns true if quoted string is substring of string
.length-1
index of last char in string index of last element of an array
arr.index(" ")
where string is in quotes, returns index of string
calling a method that takes in parameters
type method(arg1, arg2, ...)
arguments
particular data values that we pass into a method when called
-
subtract two numbers
iterate over each element of array using enumerable
arr.each {|ele| <what to do>} arr.each_with_index{|ele,idx| <what to do>} arr.each do |ele| <what to do> end arr.each_with_index do |ele,idx| <what to do> end
puts
show formatted output
parameters
concrete names that hold data in a method definition
+
add two numbers, concatenate two strings
!
not
[0]
index of the first char in a string index of the first element of an array
arr.include?(" ")
returns true if array include the quoted string
&&
and
.unshift
used as arr.unshift(ele), adds ele to front of an array. evaluates to the array.
*
multiply two numbers, repeat string contents
==
check if two elements equal one another
||
or
.push
used as arr.push(ele1,ele2,...), adds elements to end of an array. evaluates to the array.
#
comment out a line of code
>
check if one number is greater than another
Section 2
(15 cards)