I have a large list with elements as:
#1
#10
(on
)
0.0574
122-124
122A
Cat
Dog
elephant
elephant12
elephant-1
I want to search and be able to find only the following:
Cat
Dog
elephant
elephant12
elephant-1
i.e. elements which have an English alphabet at the beginning.
Use list comprehension:
import string
result = [item for item in my_list if item[0] in string.ascii_letters]
As #Jon commented, check if a character is a letter can simply be:
result = [item for item in my_list if item[0].isalpha()]
The above works when all items are string, and you expect items with leading English character. Change the if part as needed or even write a function if it is too complex.
If you are looking for memory-optimized version, consider generator.
You could work with a list of animals.
for example:
list=["cat","dog","elephant","fish","bird", "snake"]
then search for any of those strings in your input
I know there are better methods but I would do it with
def search(input):
for item in list:
if item in input:
result.append(item)
return result
Then you would add case ignorance precisions.
If you want the number associated with your animal name, you'll need to append the input. In this case, iterate your input.
Of course your list could take the dimension of a database if you need, for example to search for all possible existing word.
Related
I have the following list:
original_list = [('Anger', 'Envy'), ('Anger', 'Exasperation'), ('Joy', 'Zest'), ('Sadness', 'Suffering'), ('Joy', 'Optimism'), ('Surprise', 'Surprise'), ('Love', 'Affection')]
I am trying to create a random list comprising of the 2nd element of the tuples (of the above list) using the random method in such a way that duplicate values appearing as the first element are only considered once.
That is, the final list I am looking at, will be:
random_list = [Exasperation, Suffering, Optimism, Surprise, Affection]
So, in the new list random_list, strings Envy and Zest are eliminated (as they are appearin the the original list twice). And the process has to randomize the result, i.e. with each iteration would produce a different list of Five elements.
May I ask somebody to show me the way how may I do it?
You can use dictionary to filter the duplicates from original_list (shuffled before with random.sample):
import random
original_list = [
("Anger", "Envy"),
("Anger", "Exasperation"),
("Joy", "Zest"),
("Sadness", "Suffering"),
("Joy", "Optimism"),
("Surprise", "Surprise"),
("Love", "Affection"),
]
out = list(dict(random.sample(original_list, len(original_list))).values())
print(out)
Prints (for example):
['Optimism', 'Envy', 'Surprise', 'Suffering', 'Affection']
I am quite new to python.
And i want to only get a certain format from a bigger list, example:
Whats in the list:
/ABC/EF213
/ABC/EF
/ABC/12AC4
/ABC/212
However the only on i want listed are the ones with this format /###/##### while the rest gets discarded
You could use a generator expression or a for loop to check each element of the list to see if it matches a pattern. One way of doing this would be to check if the item matches a regex pattern.
As an example:
import re
original_list = ["Item I don't want", "/ABC/EF213", "/ABC/EF", "/ABC/12AC4", "/ABC/212", "123/456", "another useless item", "/ABC/EF"]
filtered_list = [item for item in original_list if re.fullmatch("\/\w+\/\w+", item) is not None]
print(filtered_list)
outputs
['/ABC/EF213', '/ABC/EF', '/ABC/12AC4', '/ABC/212', '/ABC/EF']
If you need help making regex patterns, there are many great websites such as regexr which can help you
Every String can be used as a list without any conversion. If the only format you want to check is /###/##### then you can simply make if commands like these:
for text in your_list:
if len(text) == 10 and text[0] == "/" and text[4] == "/" (and so on):
print(text)
Of course this would require a lot of if statements and would take a pretty long time. So I would recomend doing a faster and simpler scan. We could perform this one by, for example, splitting the texts, which would look something like this:
for text in your_list:
checkstring = text.split("/")
Now you have your text Split in parts, and you can simply check what lengths these new parts have with the len() command.
I'm kinda new to python.I'm trying to define a function when asked would give an output of only unique words which are palindromes in a string.
I used casefold() to make it case-insensitive and set() to print only uniques.
Here's my code:
def uniquePalindromes(string):
x=string.split()
for i in x:
k=[]
rev= ''.join(reversed(i))
if i.casefold() == rev.casefold():
k.append(i.casefold())
print(set(k))
else:
return
I've tried to run this line
print( uniquePalindromes('Hanah asked Sarah but Sarah refused') )
The expected output should be ['hanah','sarah'] but its returning only {'hanah'} as the output. Please help.
Your logic is sound, and your function is mostly doing what you want it to. Part of the issue is how you're returning things - all you're doing is printing the set of each individual word. For example, when I take your existing code and do this:
>>> print(uniquePalindromes('Hannah Hannah Alomomola Girafarig Yes Nah, Chansey Goldeen Need log'))
{'hannah'}
{'alomomola'}
{'girafarig'}
None
hannah, alomomola, and girafarig are the palindromes I would expect to see, but they're not given in the format I expect. For one, they're being printed, instead of returned, and for two, that's happening one-by-one.
And the function is returning None, and you're trying to print that. This is not what we want.
Here's a fixed version of your function:
def uniquePalindromes(string):
x=string.split()
k = [] # note how we put it *outside* the loop, so it persists across each iteration without being reset
for i in x:
rev= ''.join(reversed(i))
if i.casefold() == rev.casefold():
k.append(i.casefold())
# the print statement isn't what we want
# no need for an else statement - the loop will continue anyway
# now, once all elements have been visited, return the set of unique elements from k
return set(k)
now it returns roughly what you'd expect - a single set with multiple words, instead of printing multiple sets with one word each. Then, we can print that set.
>>> print(uniquePalindromes("Hannah asked Sarah but Sarah refused"))
{'hannah'}
>>> print(uniquePalindromes("Hannah and her friend Anna caught a Girafarig and named it hannaH"))
{'anna', 'hannah', 'girafarig', 'a'}
they are not gonna like me on here if I give you some tips. But try to divide the amount of characters (that aren't whitespace) into 2. If the amount on each side is not equivalent then you must be dealing with an odd amount of letters. That means that you should be able to traverse the palindrome going downwards from the middle and upwards from the middle, comparing those letters together and using the middle point as a "jump off" point. Hope this helps
Starting out by saying this is for school and I'm still learning so I'm not looking for a direct solution.
What I want to do is take an input from a user (one word or more).
I then make it in to a list.
I have my dictionary and the code that I'm posting is printing out the values correctly.
My question is how do I compare the characters in my list to the keys in the dictionary and then print only those values that correspond to the keys?
I have also read a ton of different questions regarding dictionaries but it was no help at all.
Example on output;
Word: wow
Output: 96669
user_word = input("Please enter a word: ")
user_listed = list(user_word)
def keypresses():
my_dict = {'.':1, ',':11, '?':111, '!':1111, ':':11111, 'a':2, 'b':22, 'c':222, 'd':3, 'e':33, 'f':333, 'g':4, 'h':44,
'i':444, 'j':5, 'k':55, 'l':555, 'm':6, 'n':66, 'o':666, 'p':7, 'q':77, 'r':777, 's':7777, 't':8, 'u':88,
'v':888, 'w':9, 'x':99, 'y':999, 'z':9999, ' ':0}
for key, value in my_dict.items():
print(value)
I am not going to hand you code for the project, but I will definitely send you in a right direction;
so, 2 parts to this in my view; match each character to a key/get a value, and combine the numbers for an output.
For the first part, you can iterate character-by-character by simply making a for loop;
for letter in 'string':
print(letter)
would output s t r i n g. So you can use this to find the value of the key(each letter)
Then, you can get the definition as a string(so as not to add each number mathematically) so something like;
letter = 'w'
value = my_dict[letter]
value_as_string = str(value)
then, combine this all into a for loop and add each string to each other to create the desired output.
I'm taking a programming class and have our first assignment. I understand how it's supposed to work, but apparently I haven't hit upon the correct terms to search to get help (and the book is less than useless).
The assignment is to take a provided data set (names and numbers) and perform some manipulation and computation with it.
I'm able to get the names into a list, and know the general format of what commands I'm giving, but the specifics are evading me. I know that you refer to the numbers as names[0][1], names[1][1], etc, but not how to refer to just that record that is being changed. For example, we have to have the program check if a name begins with a letter that is Q or later; if it does, we double the number associated with that name.
This is what I have so far, with ??? indicating where I know something goes, but not sure what it's called to search for it.
It's homework, so I'm not really looking for answers, but guidance to figure out the right terms to search for my answers. I already found some stuff on the site (like the statistics functions), but just can't find everything the book doesn't even mention.
names = [("Jack",456),("Kayden",355),("Randy",765),("Lisa",635),("Devin",358),("LaWanda",452),("William",308),("Patrcia",256)]
length = len(names)
count = 0
while True
count < length:
if ??? > "Q" # checks if first letter of name is greater than Q
??? # doubles number associated with name
count += 1
print(names) # self-check
numberNames = names # creates new list
import statistics
mean = statistics.mean(???)
median = statistics.median(???)
print("Mean value: {0:.2f}".format(mean))
alphaNames = sorted(numberNames) # sorts names list by name and creates new list
print(alphaNames)
first of all you need to iter over your names list. To do so use for loop:
for person in names:
print(person)
But names are a list of tuples so you will need to get the person name by accessing the first item of the tuple. You do this just like you do with lists
name = person[0]
score = person[1]
Finally to get the ASCII code of a character, you use ord() function. That is going to be helpful to know if name starts with a Q or above.
print(ord('A'))
print(ord('Q'))
print(ord('R'))
This should be enough informations to get you started with.
I see a few parts to your question, so I'll try to separate them out in my response.
check if first letter of name is greater than Q
Hopefully this will help you with the syntax here. Like list, str also supports element access by index with the [] syntax.
$ names = [("Jack",456),("Kayden",355)]
$ names[0]
('Jack', 456)
$ names[0][0]
'Jack'
$ names[0][0][0]
'J'
$ names[0][0][0] < 'Q'
True
$ names[0][0][0] > 'Q'
False
double number associated with name
$ names[0][1]
456
$ names[0][1] * 2
912
"how to refer to just that record that is being changed"
We are trying to update the value associated with the name.
In theme with my previous code examples - that is, we want to update the value at index 1 of the tuple stored at index 0 in the list called names
However, tuples are immutable so we have to be a little tricky if we want to use the data structure you're using.
$ names = [("Jack",456), ("Kayden", 355)]
$ names[0]
('Jack', 456)
$ tpl = names[0]
$ tpl = (tpl[0], tpl[1] * 2)
$ tpl
('Jack', 912)
$ names[0] = tpl
$ names
[('Jack', 912), ('Kayden', 355)]
Do this for all tuples in the list
We need to do this for the whole list, it looks like you were onto that with your while loop. Your counter variable for indexing the list is named count so just use that to index a specific tuple, like: names[count][0] for the countth name or names[count][1] for the countth number.
using statistics for calculating mean and median
I recommend looking at the documentation for a module when you want to know how to use it. Here is an example for mean:
mean(data)
Return the sample arithmetic mean of data.
$ mean([1, 2, 3, 4, 4])
2.8
Hopefully these examples help you with the syntax for continuing your assignment, although this could turn into a long discussion.
The title of your post is "Need help working with lists within lists" ... well, your code example uses a list of tuples
$ names = [("Jack",456),("Kayden",355)]
$ type(names)
<class 'list'>
$ type(names[0])
<class 'tuple'>
$ names = [["Jack",456], ["Kayden", 355]]
$ type(names)
<class 'list'>
$ type(names[0])
<class 'list'>
notice the difference in the [] and ()
If you are free to structure the data however you like, then I would recommend using a dict (read: dictionary).
I know that you refer to the numbers as names[0][1], names[1][1], etc, but
not how to refer to just that record that is being changed. For
example, we have to have the program check if a name begins with a
letter that is Q or later; if it does, we double the number associated
with that name.
It's not entirely clear what else you have to do in this assignment, but regarding your concerns above, to reference the ith"record that is being changed" in your names list, simply use names[i]. So, if you want to access the first record in names, simply use names[0], since indexing in Python begins at zero.
Since each element in your list is a tuple (which can also be indexed), using constructs like names[0][0] and names[0][1] are ways to index the values within the tuple, as you pointed out.
I'm unsure why you're using while True if you're trying to iterate through each name and check whether it begins with "Q". It seems like a for loop would be better, unless your class hasn't gotten there yet.
As for checking whether the first letter is 'Q', str (string) objects are indexed similarly to lists and tuples. To access the first letter in a string, for example, see the following:
>>> my_string = 'Hello'
>>> my_string[0]
'H'
If you give more information, we can help guide you with the statistics piece, as well. But I would first suggest you get some background around mean and median (if you're unfamiliar).