Welcome TurkHackTeam family, after a long time, I decided to write the 5th part of the Python tutorials. Because of my exams, I couldn't write much about the subject, but now I'm back. I will write topics again in my spare time.
If you want to take a look at previous tutorials:
Python Tutorial- Part 1 //"P4RS
Python Tutorial- Part 2 //"P4RS
Python Tutorial- Part 3 //"P4RS
Python Tutorial- Part 4 //"P4RS
These links go to Turkish tutorials.
I had the first 4 tutorials done quickly because it was planned for something different, I had stocked up. However, it has been a long time since I could not stock this 5th series. I extended it a lot, let's go to the subject now.
Let's start with the dictionary data type.
Dictionaries will make our work easier, just like the types of data we saw in past lessons. As with other data types, the dictionary data type also has its own methods. First, let's talk about how dictionaries are defined.
How to Define the Dictionary?
The dictionary in Python is like the language dictionary we use in real life. So when you search for the word tree in the dictionary, it will extract the word tree.
Please take a look at how we define it. The important part here is the fancy brackets. To see the data type as an example:
As you can see it said dict so, dictionary. I think the real bomb is here because most people think that this dictionary consists of two elements. However, it does not consist of two elements. It consists of a single item.
For example, we can create our dictionary from more than one item.
As you can see, our dictionary consists of two items here, too. But if you add more than one item to your dictionary and write them side by side like I did, it will look bad. Instead, I recommend using it like this:
If you write in this way, you will understand what is what when you look at your codes in the future, and when you share your codes publicly, the people who examine your codes will not have difficulty understanding.
Now we have created our dictionary, but how do we access the dictionary? Let's take a look at this.
Accessing the Dictionary
If you want, let's continue with our dictionary above. Now, let's recall one item from our dictionary.
As you can see, we called one item from our dictionary, so here's what we'll understand, to call items in dictionaries:
dictionary [item_name_in_dictionary]
If you try to call an item that is not in the dictionary, it will throw "KeyError" error.
Let's make an example with you so that we can consolidate the event a little more. As an example, let's create address information as dictionary structure.
This is how we created a dictionary. Now let's run the code we wrote and enter a name.
He gave us the address because there was such a person in the dictionary. So if there is no such person, what will it return?
Of course it will return the code block we wrote with else.
We have always used strings here, but you can also use integers. You won't get any error on this. As an example:
We learned how to create a dictionary and print the items in the dictionaries, now let's take a look at adding items to the dictionaries.
Adding Items to Dictionaries
It is easy to add items to dictionaries. Now the logic is as follows:
dictionary[word] = data
So if I need to explain on an example,
Let's see if you want to change the items as we see adding items.
Changing Items in the Dictionary
Continuing with our dictionary of numbers, let's change the numerical data together in the "dört" item here.
As you can see, we changed the numerical data in item "Dört".
Dictionaries have their own unique methods like other data types. For example;
keys()
clear()
copy()
get()
items()
values()
etc. I want to show you the use of some of them. Let's start with keys() first.
Keys()
Dictionaries work as key data. So the first part we define in the first dictionaries is the key and the next is the data. It is very easy to use.
It just brings us the keys.
Values()
The keys() method gives the keys to the dictionary, while the values () method gives us the data.
It gives us directly the data.
clear()
clear() method deletes the items in the dictionary we created.
Let's create a dictionary again
As you can see, it cleared the items inside the dictionary we created.
All the methods I'll show are these. If you are wondering about the uses of the other methods:
https://www.w3schools.com/python/python_ref_dictionary.asp You can use this link for further reading.
Functions
We have talked about many functions until our current lesson. An example is the function type(). Of course, we did not talk about a single type() function, we were introduced to str(), int() functions. Now let's talk about what is a function and what is it for us.
What Is a Function? What Does It Do?
Functions allow us to combine multiple and difficult operations and perform them in a single move. Using functions, it allows us to combine several steps into a single name.
Now let's reinforce the function structure with a few examples.
You remember the print() function. It is used to display the values taken from us on the screen. However, the important point here is that although the print() function seems to have a single function, there is a space between the parameters we press on the screen. Normally he could write on the screen like this:
veya
The print() function first left a space between the parameters (sep), then passed the bottom line (end ="\n") after printing the last parameter on the screen, displaying the outputs (file=sys.stdout). So we can do more than one operation with a single function.
So far you have understood and in your mind, "okay, how is it different from writing it as a normal variable? It's the same thing right?" There may be a question in style. Let me explain this with an example.
Now when we print it on the screen, it prints the user's information directly. But are we going to do this method over and over again when we want to change this person? So it can be done, but isn't it automating the programming logic in a little bit? I think it would be nice if we had a kullanıcı_olustur() function like print(). Let's create this together.
Creating and Using Functions
It's not something that pops up in creating a function. It is shaped by certain rules. Let's define an example function altogether.
Now when you first look at it, you may not understand something, but I'll tell you one by one. First of all, we created a function like print(), type(). We will use this function in the same way as we use other functions.
What I want to draw your attention to here is that in IDLE I use, a facilitator shows us the methods we use in our event function.
Now we have seen that it gives us the following data as output:
Normally, if we did this one by one, it would correspond to 15-20 lines, but now we have finished with 7 lines. Now when you look at these codes, it may seem a bit complicated, but it has a very simple structure. Here are what we can deduce from the code structure:
1- Functions start with def.
2- We give a name to our function.
3- We open parentheses and enter the arguments we want.
4- We end the function that starts with def by putting ":".
5- When you press Enter, we see that there is an indented space.
6- It is outside the indented space in the part written as kullanici_olustur(değer1,değer2,değer3).
You can understand all 6 items with your own observations. Now there are two important points, the recessed part and the non-recessed part, so the indented part
This is where we call the function, the function call. So functions consist of two parts. The first part is creating the function, the second part is calling the function.
The functions we have learned so far are called "builtin functions" embedded in type (), print () functions. They got this name because they are already installed in Python.
Function Structure
We use the word def to describe functions.
def indicates that we are defining a function. kullanici_olustur indicates the name of the function. We use this name when calling the function. At the end of the function: it passes to an indented (4-line space) line at the end. Here we write what to do with the function.
Now we created the function but we didn't call it. Let's run our code and what will it print out on the screen?
Of course it won't give any output because we didn't call our function. Consider the functions print(), type(), we call these functions and print something on the screen. We have to call the function after leaving the indented part.
Let's reinforce it with another example. Let's do the addition process with you. First, let's define a function named addition. Next, let's enter the parameters. Then, let's enter the indented line after putting a colon. Let's specify what we want to do with the function, since I will add here, we declare that we want to add the parameters we specified by typing print ("Toplamları:", sayi1 + number2 + number3).
Next, let's exit the body of the function, get out of the function and call the function.
I explained the function structure and creation. Through these structures here, you can write more complicated functions.
I was talking about the concepts of arguments and parameters from the beginning. Let's explain them now.
What are Arguments and Parameters?
Parameters are the parts we define in parentheses that we define in functions. For example:
We have defined a function named toplama() and added three parameters. These are sayi1, sayi2, sayi3. These parameters are used in variables in the body of the function. It will be shaped according to the values entered by the person who will run the function.
It would be better if the names you give parameters are shaped by what it does. In other words, the person running the function will have no difficulty understanding the operation of the function.
Now let's call the function:
We called the function and it gave us the sum of three as output. The numbers we call values here are arguments. But generally the two are used interchangeably. So it is not paid much attention.
Sequence is very important in functions. So when you enter the first argument, it identifies with the first parameter, when you enter the second argument, it identifies with the second parameter. So you have to do the order correctly or things will get messy.
Although it doesn't seem much difference in the addition function, let's create a record function and see the difference.
As you can see, the output is mixed. Such parameters are called sequential parameters. We also have sequential parameters. Even if the order is mixed in these, it is not a problem because it shows you which parameter will correspond.
He gave the output in a sequential manner. As you can see, it gave the arguments properly.
This tutorial ends here. We will continue the functions in the next tutorial. Have Good Forums
)
Source: https://www.turkhackteam.org/python/1928053-python-egitimi-part-5-a.html
Translator: Dolyetyus
If you want to take a look at previous tutorials:
Python Tutorial- Part 1 //"P4RS
Python Tutorial- Part 2 //"P4RS
Python Tutorial- Part 3 //"P4RS
Python Tutorial- Part 4 //"P4RS
These links go to Turkish tutorials.
I had the first 4 tutorials done quickly because it was planned for something different, I had stocked up. However, it has been a long time since I could not stock this 5th series. I extended it a lot, let's go to the subject now.
Let's start with the dictionary data type.
Dictionaries will make our work easier, just like the types of data we saw in past lessons. As with other data types, the dictionary data type also has its own methods. First, let's talk about how dictionaries are defined.
How to Define the Dictionary?
The dictionary in Python is like the language dictionary we use in real life. So when you search for the word tree in the dictionary, it will extract the word tree.
Kod:
>>> sozluk = {"ağaç" : "tree"}Please take a look at how we define it. The important part here is the fancy brackets. To see the data type as an example:
Kod:
>>> type(sozluk)
<class 'dict'>As you can see it said dict so, dictionary. I think the real bomb is here because most people think that this dictionary consists of two elements. However, it does not consist of two elements. It consists of a single item.
Kod:
>>> len(sozluk)
1For example, we can create our dictionary from more than one item.
Kod:
>>> sozluk = {"ağaç" : "tree", "araba" : "car"}
>>> len(sozluk)
2As you can see, our dictionary consists of two items here, too. But if you add more than one item to your dictionary and write them side by side like I did, it will look bad. Instead, I recommend using it like this:
Kod:
>>> sozluk = {"ağaç" : "tree",
"araba" : "car",
"bilgisayar" : "computer",
"film afişi" : "movie poster"}
>>> len(sozluk)
4If you write in this way, you will understand what is what when you look at your codes in the future, and when you share your codes publicly, the people who examine your codes will not have difficulty understanding.
Now we have created our dictionary, but how do we access the dictionary? Let's take a look at this.
Accessing the Dictionary
If you want, let's continue with our dictionary above. Now, let's recall one item from our dictionary.
Kod:
>>> print(sozluk["ağaç"])
treeAs you can see, we called one item from our dictionary, so here's what we'll understand, to call items in dictionaries:
dictionary [item_name_in_dictionary]
If you try to call an item that is not in the dictionary, it will throw "KeyError" error.
Kod:
>>> print(sozluk["deneme"])
Traceback (most recent call last):
File "<pyshell#11>", line 1, in <module>
print(sozluk["deneme"])
KeyError: 'deneme'Let's make an example with you so that we can consolidate the event a little more. As an example, let's create address information as dictionary structure.
Kod:
adres = {"Ahmet" : "Esentepe mahallesi, Atatürk caddesi, 134. Sokak, 3 / 5, Üsküdar / Istanbul",
"Mehmet" : "Esentepe mahallesi, Atatürk caddesi, 130. Sokak, 3 / 8, Üsküdar / Istanbul",
"Ali" : "Gündoğan mahallesi, Yeşildere caddesi, 40. sokak, 5 / 6, Karesi / Balıkesir"}
isim = input("Adresini öğrenmek istediğiniz kişi: ")
if isim in adres:
cevap = "{} isimli kişinin adresi: {}"
print(cevap.format(isim, adres[isim]))
else:
print("Böyle bir kişinin adresi yoktur.")This is how we created a dictionary. Now let's run the code we wrote and enter a name.
Kod:
Adresini öğrenmek istediğiniz kişi: Ali
Ali isimli kişinin adresi: Gündoğan mahallesi, Yeşildere caddesi, 40. sokak, 5 / 6, Karesi / BalıkesirHe gave us the address because there was such a person in the dictionary. So if there is no such person, what will it return?
Kod:
Adresini öğrenmek istediğiniz kişi: Alara
Böyle bir kişinin adresi yoktur.Of course it will return the code block we wrote with else.
We have always used strings here, but you can also use integers. You won't get any error on this. As an example:
Kod:
>>> sayılar = {"Sıfır" : 0,
"Bir" : 1,
"İki" : 2}
>>> print(sayılar["Sıfır"])
0We learned how to create a dictionary and print the items in the dictionaries, now let's take a look at adding items to the dictionaries.
Adding Items to Dictionaries
It is easy to add items to dictionaries. Now the logic is as follows:
dictionary[word] = data
So if I need to explain on an example,
Kod:
>>> sayılar["Dört"] = 4
>>> print(sayılar["Dört"])
4Let's see if you want to change the items as we see adding items.
Changing Items in the Dictionary
Continuing with our dictionary of numbers, let's change the numerical data together in the "dört" item here.
Kod:
>>> sayılar["Dört"] = 5
>>> print(sayılar)
{'Sıfır': 0, 'Bir': 1, 'İki': 2, 'Dört': 5}As you can see, we changed the numerical data in item "Dört".
Dictionaries have their own unique methods like other data types. For example;
keys()
clear()
copy()
get()
items()
values()
etc. I want to show you the use of some of them. Let's start with keys() first.
Keys()
Dictionaries work as key data. So the first part we define in the first dictionaries is the key and the next is the data. It is very easy to use.
Kod:
>>> print(sayılar.keys())
dict_keys(['Sıfır', 'Bir', 'İki', 'Dört'])It just brings us the keys.
Values()
The keys() method gives the keys to the dictionary, while the values () method gives us the data.
Kod:
>>> print(sayılar.values())
dict_values([0, 1, 2, 5])It gives us directly the data.
clear()
clear() method deletes the items in the dictionary we created.
Let's create a dictionary again
Kod:
>>> print(sozluk)
{'araba': 'car', 'ağaç': 'tree', 'film': 'movie'}
>>> sozluk.clear()
>>> print(sozluk)
{}As you can see, it cleared the items inside the dictionary we created.
All the methods I'll show are these. If you are wondering about the uses of the other methods:
https://www.w3schools.com/python/python_ref_dictionary.asp You can use this link for further reading.
Functions
We have talked about many functions until our current lesson. An example is the function type(). Of course, we did not talk about a single type() function, we were introduced to str(), int() functions. Now let's talk about what is a function and what is it for us.
What Is a Function? What Does It Do?
Functions allow us to combine multiple and difficult operations and perform them in a single move. Using functions, it allows us to combine several steps into a single name.
Now let's reinforce the function structure with a few examples.
Kod:
>>> print("P4RS", "THT")
P4RS THTYou remember the print() function. It is used to display the values taken from us on the screen. However, the important point here is that although the print() function seems to have a single function, there is a space between the parameters we press on the screen. Normally he could write on the screen like this:
Kod:
P4RSTHT
Kod:
THTP4RSThe print() function first left a space between the parameters (sep), then passed the bottom line (end ="\n") after printing the last parameter on the screen, displaying the outputs (file=sys.stdout). So we can do more than one operation with a single function.
So far you have understood and in your mind, "okay, how is it different from writing it as a normal variable? It's the same thing right?" There may be a question in style. Let me explain this with an example.
Kod:
ad = "Ahmet"
soyad = "Veli"
sehir = "İstanbul"
print("İsminiz: ",ad)
print("Soyadınız: ",soyad)
print("Yaşadığınız Şehir: ",sehir)Now when we print it on the screen, it prints the user's information directly. But are we going to do this method over and over again when we want to change this person? So it can be done, but isn't it automating the programming logic in a little bit? I think it would be nice if we had a kullanıcı_olustur() function like print(). Let's create this together.
Creating and Using Functions
It's not something that pops up in creating a function. It is shaped by certain rules. Let's define an example function altogether.
Kod:
def kullanici_olustur(ad,soyad,sehir):
print("İsmi: ",ad)
print("Soyadı: ",soyad)
print("Yaşadığı Şehir: ",sehir)Now when you first look at it, you may not understand something, but I'll tell you one by one. First of all, we created a function like print(), type(). We will use this function in the same way as we use other functions.
What I want to draw your attention to here is that in IDLE I use, a facilitator shows us the methods we use in our event function.
Kod:
def kullanici_olustur(ad,soyad,sehir):
print("İsmi: ",ad)
print("Soyadı: ",soyad)
print("Yaşadığı Şehir: ",sehir)
print("*"*15)
kullanici_olustur("Ahmet","Veli","İstanbul")
kullanici_olustur("Alara","Deniz","Bursa")Now we have seen that it gives us the following data as output:
Normally, if we did this one by one, it would correspond to 15-20 lines, but now we have finished with 7 lines. Now when you look at these codes, it may seem a bit complicated, but it has a very simple structure. Here are what we can deduce from the code structure:
1- Functions start with def.
2- We give a name to our function.
3- We open parentheses and enter the arguments we want.
4- We end the function that starts with def by putting ":".
5- When you press Enter, we see that there is an indented space.
6- It is outside the indented space in the part written as kullanici_olustur(değer1,değer2,değer3).
You can understand all 6 items with your own observations. Now there are two important points, the recessed part and the non-recessed part, so the indented part
Kod:
def kullanici_olustur(ad,soyad,sehir):
print("İsmi: ",ad)
print("Soyadı: ",soyad)
print("Yaşadığı Şehir: ",sehir)
print("*"*15)
burası fonksiyonun tanım kısmıdır yani function definition ikinci kısım yani girintisiz kısım
kullanici_olustur("Ahmet","Veli","İstanbul")
kullanici_olustur("Alara","Deniz","Bursa")This is where we call the function, the function call. So functions consist of two parts. The first part is creating the function, the second part is calling the function.
The functions we have learned so far are called "builtin functions" embedded in type (), print () functions. They got this name because they are already installed in Python.
Function Structure
We use the word def to describe functions.
Kod:
def kullanici_olustur(ad,soyad,sehir):def indicates that we are defining a function. kullanici_olustur indicates the name of the function. We use this name when calling the function. At the end of the function: it passes to an indented (4-line space) line at the end. Here we write what to do with the function.
Now we created the function but we didn't call it. Let's run our code and what will it print out on the screen?
Of course it won't give any output because we didn't call our function. Consider the functions print(), type(), we call these functions and print something on the screen. We have to call the function after leaving the indented part.
Let's reinforce it with another example. Let's do the addition process with you. First, let's define a function named addition. Next, let's enter the parameters. Then, let's enter the indented line after putting a colon. Let's specify what we want to do with the function, since I will add here, we declare that we want to add the parameters we specified by typing print ("Toplamları:", sayi1 + number2 + number3).
Next, let's exit the body of the function, get out of the function and call the function.
Kod:
def toplama(sayi1,sayi2,sayi3):
print("Toplamları: ",sayi1+sayi2+sayi3)
toplama(20,233,214)I explained the function structure and creation. Through these structures here, you can write more complicated functions.
I was talking about the concepts of arguments and parameters from the beginning. Let's explain them now.
What are Arguments and Parameters?
Parameters are the parts we define in parentheses that we define in functions. For example:
Kod:
def toplama(sayi1,sayi2,sayi3):
print("Toplamları: ",sayi1+sayi2+sayi3)We have defined a function named toplama() and added three parameters. These are sayi1, sayi2, sayi3. These parameters are used in variables in the body of the function. It will be shaped according to the values entered by the person who will run the function.
It would be better if the names you give parameters are shaped by what it does. In other words, the person running the function will have no difficulty understanding the operation of the function.
Now let's call the function:
Kod:
toplama(20,233,214)We called the function and it gave us the sum of three as output. The numbers we call values here are arguments. But generally the two are used interchangeably. So it is not paid much attention.
Sequence is very important in functions. So when you enter the first argument, it identifies with the first parameter, when you enter the second argument, it identifies with the second parameter. So you have to do the order correctly or things will get messy.
Although it doesn't seem much difference in the addition function, let's create a record function and see the difference.
Kod:
def kayit_olusturma(ad,soyad,sehir):
print("Ad: ",ad)
print("Soyad: ",soyad)
print("Şehir: ",sehir)
kayit_olusturma("İstanbul","Can","Veli")
Ad: İstanbul
Soyad: Can
Şehir: VeliAs you can see, the output is mixed. Such parameters are called sequential parameters. We also have sequential parameters. Even if the order is mixed in these, it is not a problem because it shows you which parameter will correspond.
Kod:
def kayit_olusturma(ad,soyad,sehir):
print("Ad: ",ad)
print("Soyad: ",soyad)
print("Şehir: ",sehir)
kayit_olusturma(ad="Can", sehir="Ankara", soyad="Veli")He gave the output in a sequential manner. As you can see, it gave the arguments properly.
This tutorial ends here. We will continue the functions in the next tutorial. Have Good Forums
)
Source: https://www.turkhackteam.org/python/1928053-python-egitimi-part-5-a.html
Translator: Dolyetyus
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