Trying to get my head around programming, I cannot work out why this doesn't work? Am I using "not" and "in" incorrectly?
I am trying to get the program to only print the characters that appear in both the strings. It correctly identifies them, but I can't get it to only print one set of the characters if there is more than one occurrence.
a = input("string1 :")
b = input("string2: ")
list1 = []
for i in a:
for j in b:
if i == j and i not in list1:
list1.append([i])
break
print(list1)
For example if you print the strings "alexander" and "alex" it will print the characters a, l, e, x, a, e
I know this current method only works if string1 is inputted as the main string, but I am just interested as to why this doesn't work.
The problem is that instead of adding the common letter to the list1, you are adding a new list containing only the common letter to list1. At the end you have a list of lists. At the same time you are checking if a single letter is in the list of lists, which will be always false.
You should just add the common letter "i" to the list using append:
a = input("string1 :")
b = input("string2: ")
list1 = []
for i in a:
for j in b:
if i == j and i not in list1:
list1.append(i)
break
print(list1)
You could also just convert string a and b to sets and intersect them:
print set(a) & set(b)
Related
List<String> pisah = ['saya','sedang','belajar','menjadi','programmer','yang','handal','dan','menyenangkan'];
How can I make that list so that I can print just every first letter of the word
example like :
baris 1 : S S B M P Y H D M
That's all in a day's work for the method map.
final letters = pisah.map((s) => s[0]).toList();
print(letters);
The .toList() call may or may not be needed depending on what exactly you want to do with the result. For example, it can be omitted if you want only to iterate over it, but it's required if you need to access individual letters using letter[i].
I want to input two comma separated strings: the first a set of strings, the second a set of ranges and return substrings based on ranges, for example:
x=input("Input string to search: ")
search=x.split(',')
y=input("Input numbers to locate: ")
numbers=y.split(',')
I would then like to use the second list of ranges to print out specified characters from the first list.
An example:
Input string to search: abcdefffg,aabcdefghi,bbcccdefghi
Input numbers to locate: 1:2,2:3,5:9
I would like the output to look like this:
bc
bcd
defghi
Any suggestions? Thanks in advance!
split(':') splits a "range" into its two components. map(int, ...) converts them to integers. string[a:b] takes characters at indices a through b.
zip is an easy way to read from two different lists combined.
Let me know if you have any other questions:
x = "abcdefffg,aabcdefghi,bbcccdefghi"
search = x.split(',')
y = "1:2,2:3,5:9"
numbers = y.split(',')
results = []
for string, rng in zip(search, numbers):
start, how_many = map(int, rng.split(':'))
results.append(string[start:start+how_many])
print(" ".join(results))
# Output:
# bc bcd defghi
So I have looked around this site and others for information on how to iterate through a string on Python, find a specific substring, reverse it and check if the two equaled in order to get a Palindrome. This is the problem though since some of the test cases are challenging to get and have confused me on how to find them through indexing.
This is my code that works for all, but two test cases:
def countPalindromes(s):
count = 0
firstindex = 0
lastindex = len(str)-1
while firstindex != lastindex and firstindex <= lastindex:
ch1 = s[firstindex:lastindex]
ch2 = s[lastindex:firstindex:-1]
if ch1 == ch2:
count +=1
firstindex +=1
lastindex -=1
return count
This code works for the following Palindromes: "racecar", " ", and "abqc".
It does not work for these Palindromes "aaaa" and "abacccaba".
For "aaaa" there are 6 palindromes and for "abacccaba" there are 8 palindromes. This is where my problem occurs, and I simply can't figure it out. For the 6 palindromes for "aaaa" I get aaaa, aaa, aa, twice for each. For "abacccaba" the 8 palindromes I have no idea as I get abacccaba, bacccab, accca, ccc, aba, aba.
I understand this is a confusing question, but I am lost how to approach the problem since I only get 2 for the "aaaa" and 4 for "abacccaba". Any ideas how I would cut out the substrings and get these values?
Thanks in advance!
while firstindex != lastindex and firstindex <= lastindex: misses the case of a single character palindrome.
You're also missing the case where aa contains three palindromes, 0:1, 0:2 and 1:2.
I think you're missing some palindromes for aaaa; there are 10:
aaaa
a
a
a
a
aa
aa
aa
aaa
aaa
If single-character palindromes do not count, then we have 6.
Either way, you need to consider all substrings as possible palindromes; not only the ones in the middle. Comparing a string against its reversed self is very easy to do in Python: s == s[::-1].
Getting all the substrings is easy too:
def get_all_substrings(input_string):
length = len(input_string)
return [input_string[i:j+1] for i in range(length) for j in range(i,length)]
and filtering out strings of length < 2 is also easy:
substrings = [a for a in get_all_substrings(string) if len(a) > 1]
Combining these should be fairly straight forward:
len([a for a in get_all_substrings(string) if len(a) > 1 and a == a[::-1]])
I think you should write a function(f) individually to check if a string is a palindrome.
Then make a function(g) that selects sub-strings of letters.
Eg: in string abcd, g will select a, b, c, d, ab, bc, cd, abc, bcd, abcd. Then apply f on each of these strings individually to get the number of palindromes.
I got three list comprehensions that do some trimming in a given string. What these are doing is that in a string, it removes words that contain '/', removes certain words in the list called 'remove_set', and combines single consecutive letters into a one big word.
regex = re.compile(r'.*/.*')
parent = ' '.join([p for p in parent.split() if not regex.match(p)])
remove_set = {'hello', 'corp', 'world'}
parent = ' '.join([i for i in parent.split() if i not in remove_set])
parent = ' '.join((' ' if x else '').join(y) for x, y in itertools.groupby(parent.split(), lambda x: len(x) > 1))
For example:
string = "hello C S people in some corp/llc"
changes to
string = "CS people in some"
Can these commands can be written in one beautiful command??
Thanks in advance!
VIM: Does anyone know how to put a string from an input dialog in a list?
p.e.:
the string "3,5,12,15"
to:
list item[1] = 3
list item[2] = 5
list item[3] = 12
etc.
and how can I know how many list items there are?
From :h E714
:let l = len(list) " number of items in list
:let list = split("a b c") " create list from items in a string
In your case,
let string = "3,5,7,19"
let list = split(string, ",")
echo len(list)
Use split, len and empty functions:
let list=split(string, ',')
let list_length=len(list)
" If all you want is to check whether list is empty:
if empty(list)
throw "You must provide at least one value"
endif
Note that if you want to get a list of numbers out of the string, you will have to use map to transform list elements into numbers:
let list=map(split(string, ','), '+v:val')
Most of time you can expect strings be transformed into numbers, but sometimes such transformation is not done.