WEBVTT 0 00:00.110 --> 00:02.090 I hope you've given that a good go, 1 00:02.090 --> 00:05.090 and now I'm going to run through the solution with you. 2 00:05.450 --> 00:12.530 Here I've got those three links open and they're all documentation on w3schools for different methods 3 00:12.530 --> 00:13.580 in Python. 4 00:13.610 --> 00:17.090 The first one is a method called readlines(). 5 00:17.090 --> 00:18.770 It's really important that you have 6 00:18.770 --> 00:23.390 that 's' because there's also another method called deadline(), the singular form. 7 00:23.390 --> 00:31.510 What readlines() does is it returns all the lines in the file as a list, where each line is an item 8 00:31.510 --> 00:32.800 in the list object. 9 00:32.800 --> 00:40.240 For example, we can run this example, and you can see that inside this demo file readlines(). 10 00:40.240 --> 00:48.910 There's several lines in that file, and each line after running this method gets added as an item inside 11 00:48.910 --> 00:51.340 a list like this. 12 00:51.820 --> 00:57.640 Now the next method I showed you is the Python String replace() method. 13 00:57.640 --> 01:04.180 And what this method does is it will replace a specified phrase with another specified phrase. 14 01:04.180 --> 01:10.330 If the starting text was, "I like bananas," and you do txt.replace(), you can replace the part where 15 01:10.330 --> 01:17.050 it says bananas with apples, and when you print, you can see the end outcome changes that text to 16 01:17.050 --> 01:18.240 "I like apples." 17 01:18.570 --> 01:23.490 Now the final method that I showed you is the String strip() method. 18 01:23.490 --> 01:29.730 And what this does is it will remove the spaces at the beginning and at the end of the string. 19 01:29.730 --> 01:35.220 So if our starting text has a lot of white space at the beginning and the end, and then we do txt.strip() 20 01:35.220 --> 01:41.580 it'll get rid of all of that extra space and it ends up with just the word. 21 01:41.610 --> 01:45.480 Now if you have a space in between another word, 22 01:47.520 --> 01:48.720 like this, 23 01:48.720 --> 01:55.110 if we hit Run, then you can see that it keeps the space in between the words, but it gets rid of any 24 01:55.110 --> 01:59.430 spaces on either side, which is really, really handy. 25 01:59.430 --> 02:03.570 And you're going to see hopefully why it's really, really useful. 26 02:03.600 --> 02:10.190 So now that we've reviewed these three methods that we haven't seen before, and normally you would 27 02:10.190 --> 02:14.870 probably find these when you actually get stuck and when you're searching StackOverflow, 28 02:15.260 --> 02:22.010 but now that you're aware of those methods, let's go ahead and create a letter using our starting letter, 29 02:22.010 --> 02:23.360 .docx. 30 02:23.360 --> 02:26.480 So I'm going to go ahead and delete everything in here. 31 02:26.480 --> 02:30.140 And now let's go ahead and tackle this challenge. 32 02:30.140 --> 02:34.970 So the first thing I want to do is to get hold of all of the invited_names, 33 02:34.970 --> 02:37.370 and I want to turn them into a list. 34 02:37.370 --> 02:44.360 Now, I can, of course, rather tediously go and add some square brackets, add some quotation marks 35 02:44.360 --> 02:47.690 around it, and then add it into my main.py, 36 02:47.690 --> 02:49.430 but I don't want to do that. 37 02:49.430 --> 02:52.580 Instead, I'm going to get Python to read the file. 38 02:52.580 --> 02:58.510 So using our classic syntax, with open(), I'm going to open up that file. 39 02:58.630 --> 03:05.050 But in order to open it up, I need to specify a string, which is going to be the path that leads me 40 03:05.050 --> 03:07.540 from here to here. 41 03:07.540 --> 03:10.120 So let's think about how we might get there. 42 03:10.120 --> 03:17.470 Now this Input-Output folder is on the same hierarchical level as our current file, where we're writing 43 03:17.470 --> 03:24.880 our code, if we want to use a relative file path, we can simply say go into the current folder, which 44 03:24.880 --> 03:29.770 is mail-merge-project-start, and then find a folder called Input. 45 03:30.760 --> 03:36.790 Inside this folder called Input, we're going to go to another folder called, Names. 46 03:36.940 --> 03:43.690 And then inside that folder of Names, we're going to get hold of that file called invited_names.txt. 47 03:43.690 --> 03:48.250 And PyCharm is super clever and it helps you out with a lot of typing. 48 03:48.250 --> 03:50.260 So it saves you some time as well. 49 03:50.260 --> 03:53.650 And then I'm going to save it as names_file. 50 03:54.250 --> 03:58.900 Now that I've got this file open I'm going to go ahead and read it, 51 03:58.900 --> 04:01.600 so names_file.read(). 52 04:01.600 --> 04:06.370 And once I've read it I'm going to save it to a variable called names, 53 04:06.370 --> 04:08.830 and then I'm going to print out my 'names'. 54 04:08.830 --> 04:17.190 So now if I go ahead and hit Run my main.py, you can see that it prints out all of these names individually, 55 04:17.190 --> 04:21.120 because it's getting hold of everything that's in here and just printing it out. 56 04:21.240 --> 04:26.910 Now, at this point, I would really like these names to be in the format of a list. 57 04:26.910 --> 04:33.530 So if you remember, that's where this readlines() method is going to be really helpful because it returns 58 04:33.530 --> 04:37.580 a list containing each line inside the file as a list item. 59 04:38.360 --> 04:43.730 Now, instead of saying names_file.read, let's replace that with readlines(). 60 04:43.850 --> 04:52.070 Now when I hit Run, you can see it prints out names, and names is now magically turned into a list. 61 04:52.070 --> 05:00.590 So now that we have our list of names which we've extracted from our invited_names.txt, then we 62 05:00.590 --> 05:07.580 can go ahead and proceed to the next step, where we're going to replace this placeholder in our starting 63 05:07.580 --> 05:10.520 letter with each of these names. 64 05:10.550 --> 05:15.770 Let's go ahead and create a constant at the top which I'll call PLACEHOLDER, 65 05:15.860 --> 05:21.200 and I'm going to set it as the string which is the square brackets, 66 05:21.200 --> 05:28.570 and then the word name, because this is the string that we want to replace from our starting letter. 67 05:28.780 --> 05:32.410 The next step is to open up our starting letter. 68 05:32.410 --> 05:34.420 So again I'm going to use open(), 69 05:34.420 --> 05:36.610 and then I'm going to specify the path. 70 05:36.610 --> 05:42.070 So from here, I'm going to go into the folder that's at the same level as this file. 71 05:42.070 --> 05:44.410 So using the ./, 72 05:44.410 --> 05:47.310 and then I'm going to go into Input again, 73 05:47.310 --> 05:51.660 and then I'm going to go into, instead of names, I'm going to go to the Letters. 74 05:53.160 --> 05:58.140 And I'm going to get hold of my starting_letter.docx. 75 05:58.140 --> 06:01.320 And I'm going to open this as the letter_file. 76 06:02.010 --> 06:09.600 With the letter_file, I'm simply just going to get hold of the letter_contents by saying letter_file.read() 77 06:09.600 --> 06:10.860 . 78 06:10.860 --> 06:17.010 And this is going to be a normal read(), because I want all of the content inside that letter, and it's 79 06:17.010 --> 06:20.910 now going to be saved as a string inside my letter_contents. 80 06:21.420 --> 06:29.430 The next step is to go through the letter_contents and replace that placeholder with the actual name 81 06:29.430 --> 06:31.140 that we've got in our list. 82 06:31.440 --> 06:36.800 To do that, we'll need the second method that I showed you, which is the replace() method. 83 06:36.800 --> 06:41.120 So we can get hold of the text, call replace(), 84 06:41.120 --> 06:47.660 and then the output of this method will be a new string which has modified this text. 85 06:48.110 --> 06:50.300 In our case, we'll need a loop. 86 06:50.300 --> 06:54.170 So we can say for name in our list of names, 87 06:54.170 --> 07:01.220 let's go through each of the names in that list, and then let's get the letter_contents and replace 88 07:01.220 --> 07:08.090 the PLACEHOLDER, so the old string with a new string, which is going to be the name. 89 07:08.180 --> 07:13.820 And once we've replaced it, then we're going to save it into a new_letter. 90 07:14.930 --> 07:20.870 Now that we have our new_letter, let's go ahead and print it out and see what it looks like. 91 07:23.680 --> 07:27.730 So you can see all the contents of each of the letters being printed, 92 07:27.730 --> 07:31.870 but other than the very last letter, that looks pretty normal, 93 07:31.870 --> 07:36.220 every other letter has a new line after the name. 94 07:36.220 --> 07:40.150 So remember when we printed out each of these names? 95 07:40.240 --> 07:46.690 You can see that after each of the names that they've extracted from this list of invited_names, there's 96 07:46.690 --> 07:54.130 a new line that's being added, and you can see that with this \n. The only one that doesn't 97 07:54.130 --> 07:56.650 have a new line is the very last one. 98 07:56.770 --> 08:00.850 What we need to do is to strip the new line. 99 08:00.850 --> 08:02.530 Does that remind you of something? 100 08:02.530 --> 08:08.920 Well, we have a method that we saw called strip(), which can take away any of the spaces at the beginning 101 08:08.920 --> 08:10.480 and at the end of the string. 102 08:10.480 --> 08:17.340 And then we can end up with an output, which is the string without any of those leading and trailing 103 08:17.340 --> 08:18.150 spaces. 104 08:18.330 --> 08:23.010 We're going to loop through each of the names, and then we're going to take the name, 105 08:23.010 --> 08:26.430 and we're going to call strip on each of those names, 106 08:26.430 --> 08:31.110 and then we can save it to a variable called stripped_name. 107 08:31.920 --> 08:36.270 And now we can use that stripped_name instead of the name. 108 08:36.930 --> 08:47.130 Now, if I go ahead and print out our new_letter, you can see that each of the letters look exactly 109 08:47.130 --> 08:49.020 like how we want them to be. 110 08:49.350 --> 08:53.940 All we need to do now is to write them into a new file. 111 08:54.510 --> 09:02.210 In previous lessons, I mentioned that when you open a file that doesn't exist, Python will actually 112 09:02.210 --> 09:04.250 create that file for you. 113 09:04.430 --> 09:10.340 Again, using our with open(), I'm going to navigate to this ReadyToSend folder. 114 09:10.490 --> 09:15.350 Going from where we are in main.py, we're going to go to the Output folder, 115 09:15.350 --> 09:18.500 and then we're going to go to the ReadyToSend folder. 116 09:18.500 --> 09:24.050 And then inside the ReadyToSend folder, is where we're going to create our new file. 117 09:24.050 --> 09:27.770 So let's think about what we want our file name to look like. 118 09:28.070 --> 09:29.510 In the intro I showed you, 119 09:29.510 --> 09:36.020 this is the format for each of the files letter_for _Aang.docx, 120 09:36.020 --> 09:39.200 and then this part is replaced by each of the names. 121 09:39.200 --> 09:45.320 So let's write that, letter_for_{the name}, 122 09:45.890 --> 09:48.680 and then .docx. 123 09:48.740 --> 09:53.800 We can use an f-string to replace this part with the stripped_name. 124 09:53.800 --> 10:00.430 So now we should be creating a new_letter for each of the names in our list of names. 125 10:00.430 --> 10:06.340 And those letters are going to have the file name, letter_for_{the name}.docx. 126 10:06.340 --> 10:12.040 So now let's refer to this file as the completed_letter. 127 10:13.570 --> 10:19.180 What we want to do with this completed_letter, which at the moment is blank, is we want to write to 128 10:19.180 --> 10:19.510 it. 129 10:19.510 --> 10:27.580 So to do that, we have to change the open mode from default, which is "r" for read to "w" for write, 130 10:27.580 --> 10:33.100 and this will allow us to get our completed_letter and write to it. 131 10:33.130 --> 10:34.660 What do we want to write in there? 132 10:34.690 --> 10:38.950 Well, we want to write the new_letter that we've created of course. 133 10:40.230 --> 10:43.170 That's pretty much the end of our code, 134 10:43.170 --> 10:47.580 and all we have to do is to go ahead and hit Run. 135 10:47.820 --> 10:54.270 And once I hit Run, you can see there's a whole bunch of letters that have been generated over here, 136 10:54.270 --> 11:00.420 and if I click on each of them, you can see that the name placeholder has now been replaced, 137 11:00.420 --> 11:04.890 and I'm now ready to go to the printers and print all of these out. 138 11:05.520 --> 11:10.500 So did you manage to figure out how to complete this project? 139 11:10.530 --> 11:16.710 If not, be sure to review the relevant parts of the lessons today so that you really confident with 140 11:16.710 --> 11:19.950 what's going on and you understand all of this code. 141 11:20.580 --> 11:25.680 If you want to take a look at the completed solution, then head over to the Course Resources and you'll 142 11:25.680 --> 11:28.650 find a link to the final project code.