Strings |Section 1| Celestial warrior

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Hi, welcome again. In the previous lecture

we were talking about numbers.

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Specifically we looked at integers and

float data types so these are referred

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to as data types in Python, so integers

and floats. In this lecture we're going

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to look at strings. I already mentioned

strings in the previous lecture.

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So a string is everything that goes

inside quotes. "Hi there". That is a string.

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And of course strings can be stored in

variables and you can print those

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variables, so we're using the interactive

shell now, but of course you can use a

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part of script as we did previously.

So numbers were used to do math operations,

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but strings, strings are used for

displaying information for the user.

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So let's say you have a web application, and

you want to generate some text

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dynamically on the web page, so you'd use

would use Python on the backend and

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Python would send strings to the HTML

code and HTML would render the

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code on the web page basically that's

the idea or if you want to create a

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notepad, an editor with Python such as

Atom let's say, all these things you see

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here so my program.py selection file,

so all this would be written as

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strings inside Python and then you

display them on the interface using

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various functions, for instance if you

want to display a string on the terminal

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you'd use the print function. Now strings

have methods associated with them. What I

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mean with methods is let me go ahead

and try out a method. Methods, for

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methods you need to use the dot notation.

So you'd refer to the string which is

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string c in our case actually

variable c, but the variable is holding

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the strings so it's the same as doing

here dot, so let's do c dot, replace and

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what I want to replace is e with i.

So I'm replacing, for string here I'm

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replacing letter e with later i and what

that will do it will replace all

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the letters, all the occurrences of this

letter in the string, so you'd ask where

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can we see these method? Well that's

very easy actually. You can do dir and

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then pass the string there, any string.

It could be c, it could be an empty string

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or whatever and that will print out all

the available methods that you can use

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with strings, so let's say c dot upper.

That will cover the strings to

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upper case letters. Now if you want to

know what these methods are about you

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could ask for help.

Just do help and then c, so the

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string or just empty string dot

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here replace method of the string

instance, so string is like the blueprint

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that creates strings objects or you can

say the data type that represents texts.

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Look here. Here is the syntax, so what you

do is, you use a string like we did.

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So let's say here replace. Then you open

brackets. Here is the old item you want

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to remove from the string and then the new

item we want to replace it with i and

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then what you see here in square brackets,

that means this parameter is

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optional so you can either pass it or

not and you know in the previous case we

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didn't pass it so what Python did was

it replaced all the occurrences of the i

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item but if you want to replace only the

first occurrence you do one there and

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that will replace all the first i over

the first e with i. That's how it works

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So strings, they support functions,

so print is a function. Here. And they support

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methods like this one here and they also

support operators so you get "Here"

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plus "There" and you get "HereThere" or you

can make it more readable like that so

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an empty space is also a string and yeah

that's about strings for now and I'll

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talk to you later.

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