I'm extremely new to python and I have no idea why this code gives me this output. I tried searching around for an answer but couldn't find anything because I'm not sure what to search for.
An explain-like-I'm-5 explanation would be greatly appreciated
astring = "hello world"
print(astring[3:7:2])
This gives me : "l"
Also
astring = "hello world"
print(astring[3:7:3])
gives me : "lw"
I can't wrap my head around why.
This is string slicing in python.
Slicing is similar to regular string indexing, but it can return a just a section of a string.
Using two parameters in a slice, such as [a:b] will return a string of characters, starting at index a up to, but not including, index b.
For example:
"abcdefg"[2:6] would return "cdef"
Using three parameters performs a similar function, but the slice will only return the character after a chosen gap. For example [2:6:2] will return every second character beginning at index 2, up to index 5.
ie "abcdefg"[2:6:2] will return ce, as it only counts every second character.
In your case, astring[3:7:3], the slice begins at index 3 (the second l) and moves forward the specified 3 characters (the third parameter) to w. It then stops at index 7, returning lw.
In fact when using only two parameters, the third defaults to 1, so astring[2:5] is the same as astring[2:5:1].
Python Central has some more detailed explanations of cutting and slicing strings in python.
I have a feeling you are over complicating this slightly.
Since the string astring is set statically you could more easily do the following:
# Sets the characters for the letters in the consistency of the word
letter-one = "h"
letter-two = "e"
letter-three = "l"
letter-four = "l"
letter-six = "o"
letter-7 = " "
letter-8 = "w"
letter-9 = "o"
letter-10 = "r"
letter11 = "l"
lettertwelve = "d"
# Tells the python which of the character letters that you want to have on the print screen
print(letter-three + letter-7 + letter-three)
This way its much more easily readable to human users and it should mitigate your error.
Related
I will state the obvious that I am a beginner. I should also mention that I have been coding in Zybooks, which affects things. My textbook hasn't helped me much
I tried sub_lyric= rhyme_lyric[ : ]
Zybooks should be able to input an index number can get only that part of the sentence but my book doesnt explain how to do that. If it throws a [4:7] then it would output cow. Hopefully I have exolained everything well.
You need to set there:
sub_lyric = rhyme_lyric[start_index:end_index]
The string is as a sequence of characters and you can use string slicing to extract any sub-text from the main one. As you have observed:
sub_lyric = rhyme_lyric[:]
will copy the entire content of rhyme_lyric to sub_lyric.
To select only a portion of the text, specify the start_index (strings start with index 0) to end_index (not included).
sub_lyric = rhyme_lyric[4:7]
will extract characters in rhyme_lyric from position 4 (included) to position 7 (not included) so the result will be cow.
You can check more on string slicing here: Python 3 introduction
I am building a puzzle word game in Python. I have the correct puzzle word, and the guessed puzzle word. I want to build a third string which shows the correct letters in the guessed puzzle in the correct puzzle word, and _ at the position of the incorrect letters.
For example, say the correct word is APPLE and the guessed word is APTLE
then i want to have a third string: AP_L_
The guessed word and correct word are guaranteed to be 3 to 5 characters long, but the guessed word is not guaranteed to be the same length as the correct word
For example, correct word is TEA and the guessed word is TEAKO, then the third string should be TEA__ because the players guessed the last two letters incorrectly.
Another example, correct word is APPLE and guessed word is POP, the third string should be:
_ _ P_ _ (without space separation)
I can successfully get the matched indexes of the correct and guessed word; however, I am having problems building the third string. I just learned that strings in Python are immutable and that i cannot assign something like str1[index] = str2[index]
I have tried many things, including using lists, but i am not getting the correct answer. The attached code is my most recent attempt, would you please help me solve this?
Thank you
find the match between puzzle_word and guess
def matcher(str_a, str_b):
#find indexes where letters overlap
matched_indexes = [i for i, (a, b) in enumerate(zip(str_a, str_b)) if a == b]
result = []
for i in str_a:
result.append('_')
for value in matched_indexes:
result[value].replace('_', str_a[value])
print(result)
matcher("apple", "allke")
the output result right now is list of five "_"
cases:
correct word is APPLE and the guessed word is APTLE third
string: AP_L_
correct word is TEA and the guessed word is TEAKO,
third string should be TEA__
correct word is APPLE and guessed
word is POP, third string should be _ _ P_ _
You can use itertools.zip_longest here to always make sure you pad out to the longest word provided and then create a new string by joining the matching characters or otherwise a _. eg:
from itertools import zip_longest
correct_and_guess = [
('APPLE', 'APTLE'),
('TEA', 'TEAKO'),
('APPLE', 'POP')
]
for correct, guess in correct_and_guess:
# If characters in same positions match - show character otherwise `_`
new_word = ''.join(c if c == g else '_' for c, g in zip_longest(correct, guess, fillvalue='_'))
print(correct, guess, new_word)
Will print the following:
APPLE APTLE AP_LE
TEA TEAKO TEA__
APPLE POP __P__
Couple of things here.
str.replace() does not replace inline; as you noted strings are immutable, so you have to assign the result of replace:
result[value] = result[value].replace('_', str_a[value])
However, there's no point doing this since you can just assign to the list element:
result[value] = str_a[value]
And finally you can assign a list of the length of str_a without the for loop, which might be more readable:
result = ['_'] * len(str_a)
I have a list of strings, and I'm trying to find the position of the first letter of the substring I am searching for in the list of strings. I'm using the find() method to do this, however when I try to print the position of the first letter Python returns the correct position but then throws a -1 after it, like it couldn't find the substring, but only after it could find it. I want to know how to return the position of the first letter of he substring without returning a -1 after the correct value.
Here is my code:
mylist = ["blasdactiverehu", "sdfsfgiuyremdn"]
word = "active"
if any(word in x for x in mylist) == True:
for x in mylist:
position = x.find(word)
print(position)
The output is:
5
-1
I expected the output to just be:
5
I think it may be related to the fact the loop is searching for the substring for every string in the list and after it's found the position it still searches for more but of course returns an error as there is only one occurrence of the substring "active", however I'm not sure how to stop searching after successfully finding one substring. Any help is appreciated, thank you.
Indeed your code will not work as you want it to, since given that any of the words contain the substring, it will do the check for each and every one of them.
A good way to avoid that is using a generator. More specifically, next()
default_val = '-1'
position = next((x.find(word) for x in mylist if word in x), default_val)
print(position)
It will simply give you the position of the substring "word" for the first string "x" that will qualify for the condition if word in x, in the list 'mylist'.
By the way, no need to check for == True when using any(), it already returns True/False, so you can simply do if any(): ...
Extracting a specific word and a number of tokens on each side of it from each string in a column in SAS EG ?
For example,
row1: the sun is nice
row2: the sun looks great
row3: the sun left me
Is there a code that would produce the following result column (2 words where sun is the first):
SUN IS
SUN LOOKS
SUN LEFT
and possibly a second column with COUNT in case of duplicate matches.
So if there was 20 SUN LOOKS then it they would be grouped and have a count of 20.
Thanks
I think you can use functions findw() and scan() to do want you want. Both of those functions operate on the concept of word boundaries. findw() returns the position of the word in the string. Once you know the position, you can use scan() in a loop to get the next word or words following it.
Here is a simple example to show you the concept. It is by no means a finished or polished solution, but intended you point you in the right direction. The input data set (text) contains the sentences you provided in your question with slight modifications. The data step finds the word "sun" in the sentence and creates a variable named fragment that contains 3 words ("sun" + the next 2 words).
data text2;
set text;
length fragment $15;
word = 'sun'; * search term;
fragment_len = 3; * number of words in target output;
word_pos = findw(sentence, word, ' ', 'e');
if word_pos then do;
do i = 0 to fragmen_len-1;
fragment = catx(' ', fragment, scan(sentence, word_pos+i));
end;
end;
run;
Here is a partial print of the output data set.
You can use a combination of the INDEX, SUBSTR and SCAN functions to achieve this functionality.
INDEX - takes two arguments and returns the position at which a given substring appears in a string. You might use:
INDEX(str,'sun')
SUBSTR - simply returns a substring of the provided string, taking a second numeric argument referring to the starting position of the substring. Combine this with your INDEX function:
SUBSTR(str,INDEX(str,'sun'))
This returns the substring of str from the point where the word 'sun' first appears.
SCAN - returns the 'words' from a string, taking the string as the first argument, followed by a number referring to the 'word'. There is also a third argument that specifies the delimiter, but this defaults to space, so you wouldn't need it in your example.
To pick out the word after 'sun' you might do this:
SCAN(SUBSTR(str,INDEX(str,'sun')),2)
Now all that's left to do is build a new string containing the words of interest. That can be achieved with concatenation operators. To see how to concatenate two strings, run this illustrative example:
data _NULL_;
a = 'Hello';
b = 'World';
c = a||' - '||b;
put c;
run;
The log should contain this line:
Hello - World
As a result of displaying the value of the c variable using the put statement. There are a number of functions that can be used to concatenate strings, look in the documentation at CAT,CATX,CATS for some examples.
Hopefully there is enough here to help you.
Need to extract the initial character from a Korean word in MS-Excel and MS-Access.
When I use Left("한글",1) it will return the first syllable i.e 한, what I need is the initial character i.e ㅎ .
Is there a function to do this? or at least an idiom?
If you know how to get the Unicode value from the String I'd be able to work it out from there but I'm sure I'd be reinventing the wheel. (yet again)
Disclaimer: I know little about Access or VBA, but what you're having is a generic Unicode problem, it's not specific to those tools. I retagged your question to add tags related to this issue.
Access is doing the right thing by returning 한, it is indeed the first character of that two-character string. What you want here is the canonical decomposition of this hangul in its constituent jamos, also known as Normalization Form D (NFD), for “decomposed”. The NFD form is ᄒ ᅡ ᆫ, of which the first character is what you want.
Note also that as per your example, you seem to want a function to return the equivalent hangul (ㅎ) for the jamo (ᄒ) – there really are two different code points because they represent different semantic units (a full-fledged hangul syllable, or a part of a hangul). There is no pre-defined mapping from the former to the latter, you could write a small function to that effect, as the number of jamos is limited to a few dozens (the real work is done in the first function, NFD).
Adding to Arthur's excellent answer, I want to point out that extracting jamo from hangeul syllables is very straightforward from the standard. While the solution isn't specific to Excel or Access (it's a Python module), it only involves arithmetic expressions so it should be easily translated to other languages. The formulas, as can be seen, are identical to those in page 109 of the standard. The decomposition is returned as a tuple of integers encoded strings, which can be easily verified to correspond to the Hangul Jamo Code Chart.
# -*- encoding: utf-8 -*-
SBase = 0xAC00
LBase = 0x1100
VBase = 0x1161
TBase = 0x11A7
SCount = 11172
LCount = 19
VCount = 21
TCount = 28
NCount = VCount * TCount
def decompose(syllable):
global SBase, LBase, VBase, TBase, SCount, LCount, VCount, TCount, NCount
S = ord(syllable)
SIndex = S - SBase
L = LBase + SIndex / NCount
V = VBase + (SIndex % NCount) / TCount
T = TBase + SIndex % TCount
if T == TBase:
result = (L,V)
else:
result = (L,V,T)
return tuple(map(unichr, result))
if __name__ == '__main__':
test_values = u'항가있닭넓짧'
for syllable in test_values:
print syllable, ':',
for s in decompose(syllable): print s,
print
This is the output in my console:
항 : ᄒ ᅡ ᆼ
가 : ᄀ ᅡ
있 : ᄋ ᅵ ᆻ
닭 : ᄃ ᅡ ᆰ
넓 : ᄂ ᅥ ᆲ
짧 : ᄍ ᅡ ᆲ
I think what you are looking for is a Byte Array
Dim aByte() as byte
aByte="한글"
should give you the two unicode values for each character in the string
I assume you got what you needed, but it seems rather convoluted. I don't know anything about this, but recently did some investigating of handling Unicode, and looked into all the string Byte functions, such as LeftB(), RightB(), InputB(), InStrB(), LenB(), AscB(), ChrB() and MidB(), and there's also StrConv(), which has a vbUnicode argument. These are all functions that I'd think would be used in any double-byte context, but then, I don't work in that environment so might be missing something very important.